When both the Boston Celtics and New York Knicks got off to sputtering starts to their seasons, the Philadelphia 76ers gladly assumed the void at the top of the Atlantic Division, which simultaneously is the worst and most valuable division in the NBA.

Despite opening with a five-game road trip, the 76ers grabbed first place before arriving home and held onto it like it was a winning lottery ticket. Since Dec. 28, Philadelphia has not been out of the top spot in the Atlantic.

Until now.

With an absolutely wretched effort against one of the league’s worst teams, the Sixers relinquished first place for the first time in more than three months on Friday night, losing in Washington while the Celtics won in Minnesota.

The Sixers got off to a 20-9 start built mostly through cohesion, health and a soft early schedule. They have muddled along at 8-14 since, with virtually all of their wins coming either against bad teams or division foes. Twice this month, they were in danger of surrendering the top spot in the division but beat the Celtics in a showdown on their home floor.

And now, they appear lost.

From John Mitchell of the Philadelphia Daily News: “After the lottery-bound Washington Wizards soundly beat the 76ers in every statistical category on the way to a 97-76 victory at the Verizon Center on Friday night, the most damaging aspect is that all of a sudden the Sixers, at least to their coach, appear to be a team without an identity. The loss, coupled with Boston’s 100-79 victory over Minnesota, gives the Celtics (29-22) a one-game lead over the Sixers (28-23) in the Atlantic Division. The problem was somewhat clear at halftime when coach Doug Collins, walking with his team to the locker room, shook his head while staring at the floor and dug his hand in his pocket, looking like the perplexed father who doesn’t know what to expect from a wayward child. After a drubbing that saw the Wizards end a five-game losing streak by holding the Sixers to 36.6 percent shooting while making 48.3 percent of their own, outrebound them 52-38, collect 26 assists to the Sixers’ 19, outwork the Sixers, and look the part of the team that has playoff aspirations, Collins sounded as if he had no clue what to expect from these Sixers the next time they take the court. “For whatever reason we weren’t ready,” Collins said. “You get down and you think you are going to turn on some switch or whatever. But those guys knocked us around. They played well. Hats off to them. They played well and they deserved to beat us like they did tonight. That wasn’t even a game.” Asked what he expected of the Sixers when they face Atlanta tonight at Wells Fargo Center, Collins’ answer was puzzling. “I have no idea,” Collins said. “I have no idea.”

The Sixers dropped from fourth to seventh in the Eastern Conference standings, switching places with the Celtics in a significant shift. The winner of the Atlantic is guaranteed one of the top four seeds in the East, which means it likely won’t have to play Chicago or Miami in the first round.

It should be noted that it does not guarantee home-court advantage against the fifth seed. Right now, both Indiana and Atlanta have better records than Philadelphia and Boston and would have Game Seven at home in a potential 4-5 matchup in the first round.

It has been a long climb for the Celtics, who entered the All-Star break with five straight losses and a 15-17 mark. Despite losing three rotation players to injuries since the break, they have gone 14-5 to zoom past both New York and Philadelphia to the top of the division.

They got there because Kevin Garnett was able to corral Kevin Love. In a battle of power forwards excelling while playing out of position at center, the former Timberwolf was a bit better than the current one.

From Steve Bulpett of the Boston Herald: “The Celtics found themselves in strange and foreign territory after their 100-79 victory against the Timberwolves last night. For the first time this season, they were alone in first place in the Atlantic Division. They reached that destination largely because Kevin Garnett was in a very familiar place. The talk coming in was about the Wolves’ new Kevin, but KG showed Love no love, going after his replacement in the local pantheon on both ends of the floor. Garnett made 12-of-18 shots on the way to 24 points and 10 rebounds, while Love hit just 5-of-18 for 22 points to go with 11 boards. “I think it’s always personal,” coach Doc Rivers said. “He won’t tell you that either way, but I think everyone’s up when they come back. Kevin is the best player to ever play here. Kevin Love has a chance to be that, as well, or one of them.”

Rivers was careful to note that while the Celtics are a first-place team at the moment, there is no guarantee they will remain in that perch. As March changes to April, the schedule gets far more challenging, especially with Ray Allen and Mickael Pietrus still out of the lineup.

Here’s the lineup: Home games vs. Miami and San Antonio, visits to Chicago and Indiana, and home meetings with Philadelphia and Atlanta around a visit to Miami. That death march is followed by three winnable games, but they come on consecutive nights, all on the road.

From Chris Forsberg of ESPNBoston.com: “Needless to say, Boston is going to have to work if it wants to maintain its new-found one-game advantage atop the Atlantic Division. Boston entered Friday’s game with the toughest remaining schedule (based on winning percentage of opponents), while the path is decidedly easier for the 76ers, who also own the head-to-head tie-breaker against the Celtics in the case of a tie atop the standings. Even still, Boston has built some serious confidence in recent games and it will be interesting to see (1) How that carries over as the schedule increases in difficulty and (2) If the Celtics can maintain their strong play, all while getting back reinforcements like Allen and (potentially) Pietrus before the playoffs arrive.”

The Atlantic could have gotten even tighter had the Knicks been able to maintain their recent success. Just when it looked like that would be the case, injuries caught up to them as well.

Already without Amar’e Stoudemire and Jeremy Lin, the Knicks saw Carmelo Anthony, Tyson Chandler and Baron Davis impacted by injuries in a 100-90 loss at Atlanta that made their current hold on the eighth and final playoff spot in the East a little less comfortable.

From Ray Glier of the New York Times: “Carmelo Anthony said he felt the twinge of pain in his groin in the fourth quarter after he stripped the ball from Atlanta’s Josh Smith and saved it from going out of bounds. He knew he was in trouble, and so were the Knicks. Anthony had just completed a 3-point play with 8 minutes 56 minutes to play to bring the Knicks to within 80-78. With 8:40 left, he gathered up the loose ball after a steal, a defensive gem to go with his offensive gem of a night (36 points). But that was when he hurt himself, and he did not score another field goal as the Hawks pulled away for a 100-90 victory in Philips Arena. It was only the second loss in 10 games for the Knicks since Mike Woodson took over as their interim coach. The Knicks are 26-26, in the eighth and final playoff spot in the Eastern Conference. But they will play the Cleveland Cavaliers at Madison Square Garden on Saturday night with serious injury concerns. Point guard Jeremy Lin (left knee) did not play for the third straight game and forward Amar’e Stoudemire (back) might not be back for the rest of the regular season. The veteran guard Baron Davis was supposed to take over for Lin, but he had ice packs on his back and hamstring after the game and was ineffective Friday night (24 minutes, 4 points, 4 assists, 4 turnovers). The Knicks may also have to deal with a sudden injury to center Tyson Chandler, who said after the game that he also felt some pain in his groin. Chandler was 2 of 4 from the field in 40 minutes and could not find any room to make himself available for passes. The Knicks can survive without Lin, Stoudemire and Davis. They cannot survive without Anthony, who is rejuvenated and a force again. He made 11 of 24 field-goal attempts and 13 of 14 free throws to go along with 9 rebounds and 5 steals.”

The Knicks also have a tough upcoming schedule. After Saturday’s home game vs. slumping Cleveland, they visit Indiana and Orlando and have a home-and-home with Chicago before traveling to Milwaukee.

Elsewhere …

• The Bucks made things a little tighter in the East with a 121-84 road rout of the Cavaliers, who have lost six in a row. It was the largest margin of victory since 2002 for Milwaukee, which got 28 points from Brandon Jennings and moved within 1 1/2 games of New York for the final playoff spot. Cleveland’s Kyrie Irving, who already has Rookie of the Year locked up, made 6-of-6 3-pointers and scored 29 points, left in the fourth quarter with a shoulder injury and might be out a while.
• Again playing without Derrick Rose, the Bulls held the Pistons to a pair of 10-point quarters in an 83-71 home win. Luol Deng had 20 points and nine boards and Joakim Noah added 19 and 12 for the Bulls, whose winning percentage without Rose (14-5, .737) would be the fourth-best record in the NBA. Detroit has lost its last 14 meetings with Chicago.
• The Heat kept pace with a 113-101 win at Toronto. Miami found itself in an 89-89 tie with nine minutes to go, suddenly realized it was playing Toronto and rattled off eight straight points to take control. Dwyane Wade and Chris Bosh scored 30 points apiece and LeBron James added 26 and nine assists. The Raptors have lost 10 of 11.
• Dirk Nowitzki threw in a one-footed rainbow banker with 5.9 seconds left to cap a frantic fourth quarter as the Mavericks edged the Magic, 100-98, in a key interconference tilt, as we used to say at the AP. Nowitzki scored 28 points for Dallas, which has won six straight visits to Orlando. On the Magic’s final possession, Hedo Turkoglu clanged a 3-pointer and Ryan Anderson gagged on a gimme follow shot. Orlando is just 4-4 since Dwight Howard finally made up his mind at the trading deadline.
• In a game that had three lead changes in the final minute, the Clippers edged the visiting Trail Blazers, 98- 97, to move to 4-0 on their “Save Vinny’s Job” homestand. Chris Paul had 20 points and 14 assists, and made the go-ahead layup with five seconds to play. LA remained one game ahead of Dallas for fourth in the Western Conference. Wesley Matthews missed a runner for Portland, which was without LaMarcus Aldridge (elbow sprain).
• The win-one-lose-one Nuggets won one, managing a 99-88 road win over the awful Bobcats as Arron Afflalo had points and 12 rebounds. Denver hasn’t won consecutive games since March 4-5 but has lost two in a row just once in that span. Charlotte leading scorer Corey Maggette strained his right Achilles, which may relegate the Bobcats to single-digit wins for the season.
• The Rockets defeated the visiting Grizzlies, 98-89, and remained tied with the Nuggets for seventh in the West. Trade deadline acquisition Marcus Camby had 16 rebounds and six blocks. Goran Dragic continued his fantastic play with 25 points and is turning Kyle Lowry into Wally Pipp. Beginning a brutal stretch of seven games in nine days, Memphis fell behind Dallas into sixth in the West, just 1 1/2 games in front of Houston and Denver.
• The Jazz fell into ninth in the West – one game behind Houston and Denver – with a regrettable 104-103 home loss to the Kings. DeMarcus Cousins made a free throw with 3.8 seconds left, and Gordon Hayward’s driving layup was not close. All three games between the clubs have come down to last-second shots, with Utah winning the first two. Cousins had 27 and Marcus Thornton added 26 for Sacramento. Tyreke Evans’ irrelevance continued as he sat out with back spasms.
• For some reason, the Nets decided to rally from a 19-point deficit for a 102-100 victory at Golden State. The win kept New Jersey ahead of Toronto in the overall standings. Had the Nets lost, they would have had the fourth-worst record in the NBA, better than only Charlotte, Washington and New Orleans. If New Jersey doesn’t receive one of the top three picks in the draft lottery, its pick goes to Portland. The Warriors have lost four in a row and nine of 11.