NEW YORK — Brooklyn was playing its second game in as many nights on Sunday. The 76ers, meanwhile, were rested after having Saturday off.

Watching the game, one would have assumed it was the other way around.

The Nets appeared to have fresh legs while the Sixers looked sluggish and out of sync without Joel Embiid, who was out sick with an upper respiratory illness. That combination led to Brooklyn taking a 109-89 upset victory at the Barclays Center.

“Our energy definitely wasn’t where we wanted it to be,” Tobias Harris said. “We didn’t have enough good, solid plays to really generate us that type of energy tonight. Nor did we have enough defensive plays, either.”

The loss denied the Sixers (20-8) an opportunity to win consecutive road games since winning their first three away games of the season. They also dropped one spot -- to third place -- in the Eastern Conference standings.

The Nets (14-12), who played Saturday night in Toronto, snapped a two-game skid.

The Sixers trailed by as many as 26 points (107-81) with 2 minutes, 41 seconds remaining. They made just 5 of 26 three-pointers and missed 7 of 17 foul shots. And they had a tough time containing Brooklyn guard Spencer Dinwiddie, who drove the lane at will en route to scoring a game-high 24 points.

The Nets finished with 64 points in the paint.

“It’s a tough one,” Harris said. “I think what we can take from it is pretty much is we learn from it, take two days to rest up and be ready for the next one, and just get going.”

The Sixers will definitely welcome Embiid back when they host the Miami Heat on Wednesday night.

With Embiid out, Al Horford returned after being sidelined two games with left knee soreness and left hamstring tightness.

As he does whenever Embiid sits, Horford started at center. On this night, he struggled shooting the ball.

Horford finished with 10 points, 9 rebounds, 5 assists, 3 blocks and 1 steal. But he made just 5 of 15 shots while missing all six of his three-point attempts.

“Physically, I felt fine,” Horford said. "You know, definitely a little off, timing, rhythm stuff like that. I felt good about a lot of my possessions, offensively. They just ... shots just didn’t go down like I expected them.

“But I’ll get back to work tomorrow and get ready for the next one.”

Josh Richardson also had a tough time hitting shots, also going 5-for-15 from the field. The shooting guard went 0-for-4 on threes. He finished with 11 points and 3 turnovers.

Ben Simmons had a team-high 20 points to go with 2 blocks and a steal. Harris added 17 points, 6 rebounds, 2 blocks, and 4 turnovers. He shot 8 of 17 overall, but missed his three three-pointers.

Rookie reserve Matisse Thybulle left the game in the third quarter with an upset stomach. He failed to score a point while finishing with two steals and a blocked shot in 18:48. Thybulle thinks he may have had food poisoning. He felt ill upon waking up Sunday morning.

“I thought I was going to be able to play through it,” Thybulle said. "But the more I played, the worse it got.

“In the second half, I felt I was going to hurt the team more than I was going to help them.”

When he pushed himself offensively, he had to walk back on defense due to not feeling well.

“It didn’t seem like I was helping,” he said.

Two-way player Norvel Pelle was the Sixers’ backup center for the second consecutive game. He finished with 2 points, 4 rebounds and 2 blocks.

Former Sixer Wilson Chandler finished 2 points and 7 rebounds in his first game with the Nets. Chandler was suspended the first 25 games after testing positive for a banned growth hormone. The reserve power forward, whom the Sixers traded to the Los Angeles Clippers in the Tobias Harris deal in February, signed a free-agent deal with the Nets during the offseason.

Another former Sixer, Timothe Luwawu-Cabarrot, had 8 points on 3-for-6 shooting off the bench. All of his point came in the first half.

The Nets were without starting guards Kyrie Irving and Caris Levert.