Jefferson made a running jumper with 1.5 seconds remaining to give the Nets a 117-115 victory over the Utah Jazz on Saturday night.
"On that situation, you want to win the game or put it into overtime," said Nets coach Lawrence Frank. "Richard had a great time, great attack and he didn't settle. It was a phenomenal finish and you have to give him a lot of credit."
Jefferson said he was simply trying to make something happen.
"I was just trying to attack and get to the hole and either get something to the rim, get an open shot for my teammates or get to the free throw line. That was the ultimate goal," Jefferson said.
Carlos Boozer, who equaled his career high with 41 points for Utah, could only watch helplessly as the shot caught net.
"I was hoping it would come off so I could grab the rebound," Boozer said. "He made a hell of a shot."
Jefferson led the Nets with 27 points and Vince Carter scored 25. Josh Boone had 21 points and 13 rebounds as New Jersey posted its fifth straight home win over Utah. Devin Harris add 19 points and 12 assists.
The big night from Boozer was not enough to carry Utah to a third straight win. He had a remarkably precise game, shooting 15-of-19 from the field and 11-of-13 from the free throw line. Reserve Kyle Korver added 18 points for the Jazz.
It was the second straight victory for the Nets over a top opponent following a six-game losing streak, having beaten the Cleveland Cavaliers at home on Wednesday.
The win gave New Jersey a half-game lead over Atlanta in the fight for the eighth and final playoff spot in the Eastern Conference.
The Nets, trailing through most of the second and third quarters, battled back to tie the score at 98 when Bostjan Nachbar sank a 3-pointer with 6:38 remaining.
The set the stage for a seesaw battle to the finish. Utah seemed to have it when Korver missed a jumper and Boozer pounced for the offensive rebound and basket with 2:49 left. Boozer, fouled on the play, sank the free throw to complete the three-point play that gave the Jazz a 111-107 lead.
The Nets would not wilt, tying it at 115 when Jefferson sank two free throws with 1:05 to play.
Korver missed a 3-pointer on Utah's next possession. The Nets could not score at the other end, as Carter and Nachbar missed close-in chances.
Ronnie Brewer pulled down the rebound, giving Utah one more chance to take the lead, but Korver missed another 3-pointer. Harris got the rebound, setting the stage for Jefferson's winning basket.
"We had shots we felt we could make," Jazz coach Jerry Sloan said. "We took them but didn't make them. Richard Jefferson got the job done and you have to give him credit, because he is a great player."
Sean Williams replaced Nenad Krstic in the Nets starting lineup at forward. Krstic was inactive with an upper respiratory infection and was replaced on the bench by Maurice Ager, who suited up for the first time in four games. Williams didn't last long, picking up three fouls in the first 3:17 before being replaced by Stromile Swift. ... The Jazz completed a tough road stretch of four games in five nights, going 2-2 on the trip.