The good feelings created last month by Jeremy Lin's emergence -- along with Lin's best play -- seem long gone now.
"When we get down, it just seems like our whole energy just goes out the door," Carmelo Anthony said.
Williams scored 12 of his 28 points in a dazzling flurry, Evan Turner had 24 points and 15 rebounds, and the Philadelphia 76ers handed the Knicks their fifth straight loss with a 106-94 victory Sunday.
Williams tossed in a long jumper to beat the halftime buzzer, then had a dozen points in the final 3:28 of the third quarter, when the 76ers seized control for their third straight victory.
"I was just able to get some good looks," Williams said. "In the third quarter, played with a ton of confidence and felt like I could make any shots."
That mentality doesn't currently exist for the Knicks, with bad body language everywhere and Anthony saying they had "no type of confidence out there."
"We hit a snag and we seem to whither and for whatever reason we haven't overcome any kind of obstacles," coach Mike D'Antoni said.
Andre Iguodala had 19 points, eight assists and seven rebounds for the 76ers, who turned a competitive game into a rout to end a three-game losing streak to the Knicks.
Anthony scored 22 points but didn't make a field goal over the final three quarters, while Lin shot just 5 of 18 for 14 points with seven assists and six turnovers. Tyson Chandler had eight points and 12 rebounds after missing two games with a strained left hamstring, but he couldn't solve the Knicks' defensive woes.
Philadelphia was up by eight late in the third quarter before Williams took over. He made two 3-pointers, a pair of jumpers and two free throws as the 76ers outscored the Knicks 16-8 to open an 89-73 lead.
"Third quarter, I guess, you know they hit a lot of shots, we were a step slow on defense and I didn't take care of the ball," Lin said. "So they get easy run-outs in transition and then we didn't box out the way we should have, so more easy baskets and they get into a flow, they get into a rhythm."
Williams nailed another 3 early in the fourth, and Turner followed with two free throws to push the lead to 21.
The Sixers have rebounded from a five-game skid before the All-Star break and followed a convincing victory over Boston by beating Utah before Sunday's win. Thaddeus Young had 14 points, joining Williams in another strong performance by one of the league's best benches.
"That's our recipe," coach Doug Collins said. "I told guys after the game, I said that's what we do. There's going to be teams that we play against that will have more talent that we got to hope at the end of the day that our numbers makes us a better team. That's been our whole emphasis."
The Knicks might have hoped to catch the Atlantic Division leaders at one point but now are simply hoping to hold onto a playoff spot after entering play just two games ahead of Milwaukee and Cleveland.
They dropped all four games on their road trip and looked particularly lost without Chandler, their defensive anchor. They yielded 118 points in a loss at San Antonio and surrendered 119 on Friday against Milwaukee, and now travel to powerful Chicago on Monday.
"Yeah, it's definitely not easy," said Amare Stoudemire, who scored just nine points and sat alongside Anthony for the entire fourth quarter. "Tough game in Chicago. A lot of games within this month against tough, competitive teams. So it's up to us as players to want to do better out there."
It's not only the defensive effort. D'Antoni conceded before the games the intensity just isn't always there from his team, saying the Knicks sometimes get "lost" or "sidetracked."
And the crowd is recognizing it.
The building was often quiet, fans perhaps a little groggy after the clocks sprung forward and with an early start. But the Knicks also are not entertaining them the way they did during their seven-game winning streak last month. Lin has been solid but couldn't be expected to sustain his sensational level of play, and the Knicks are still unable to settle on their best rotation with a much deeper roster than they had back then.
Anthony, usually loudly cheered, had some boos sprinkled in when he was introduced with the starting lineups. A brief "Fire D'Antoni!" chant broke out in the final minutes, and there were some loud boos near the finish.
"Times where we went on a little spurt where we didn't make shots, guys were putting their heads down," Anthony said, "and they heard a couple of boos out there, that just sucked the whole energy out of everybody tonight out there on the basketball court and we can't have that."
The Knicks led 24-22 after one quarter behind 12 points from Anthony. But New York turned it over six times in the second, and the 76ers went up 51-49 after Williams hit a long jumper from the corner as the first half ended.
Anthony was 5 of 7 in the first quarter but missed his final six shots, mostly while guarded by fellow All-Star Iguodala.
"I pretty much take every game with the same approach. You go up against players with Carmelo's type of ability, you have to kind of focus in a little more of not letting him get certain catches, and try to keep him off his comfort zone," Iguodala said. "The team did a good job. We had a couple of spots where we doubled and helped keep the ball out of his hands and trying to keep him out of rhythm."
The Sixers are 25-17 after they were 17-25 through 42 games last season. ... Collins said center Spencer Hawes, who has a strained left Achilles and has missed 28 games, could play 2-on-2 Monday and increase his workouts throughout the week. ... D'Antoni didn't rule out forward Jared Jeffries (sore right knee) for Monday at Chicago but is aiming more for Wednesday or Friday.