Irving scored 10 of his 18 points in the fourth quarter, all in the last 2:36 of the game, and Antawn Jamison had 33 to help the Cavaliers snap a six-game losing streak.
"Kyrie down the stretch, it speaks for itself," Jamison said. "He single-handedly won the game for us."
It wasn't easy.
Neither team could pull away in the fourth quarter. Denver scored the first six points to go ahead 78-76 and the lead changed hands nine times in the final 2:36, with the point guards staging a personal duel down the stretch.
|More on Cavaliers-Nuggets|
|More NBA coverage|
Lawson, who made the decisive baskets in wins over San Antonio and Sacramento in the last week, had five of his 18 points in the finishing flurry to give Denver a 95-94 lead.
Irving had two three-point plays and a driving layup to put Cleveland up 98-97 with 24 seconds left.
He saved his best for the final seconds.
After Nene muscled in a layup over rookie Tristan Thompson with 15 seconds left to give Denver a 99-98 lead, Irving took the inbounds pass in the backcourt, raced up the floor into the lane and made the go-ahead basket.
"I tried to deny him the ball. He got a head of steam, got me on his hip and took it all the way," Arron Afflalo said. "We would like to first keep him in front of us and if he does get by us have some help in protecting the basket. Neither one was done. You expect on the game-winning layup someone swats on the ball."
Irving said he took Afflalo's defense as a challenge.
"He picked me up fullcourt and I take it as a test when people pick me up fullcourt," Irving said. "The lane opened up when I got down there, it was a tough shot, but my teammates willed it in."
After a timeout, Lawson got the ball at the top of the key with Irving guarding him. Despite having five fouls, Irving played aggressive defense and forced Lawson into a tough layup that he missed at the buzzer.
"I got a step on him and I seen him try to time the shot," Lawson said. "I tried to step in and get him off balance. I didn't have enough lift to finish it. It hit the rim, but it's one of those shots I need to make."
"Just keep moving forward. There's too many games to worry about one," Lawson said.
The game was tied in the third quarter before Alonzo Gee scored the next seven points to give Cleveland a 72-65 edge. The Cavs led by four heading into the fourth after Daniel Gibson's 3-pointer was ruled after the horn.
Gee finished with 19.
Jamison was the biggest reason for Cleveland leading 57-55 at the break. The forward scored 14 in the first quarter to keep the Cavaliers close, then had 12 more in the second when they overcame a nine-point deficit.
Trailing 41-32, Jamison hit two jumpers and a pair of free throws to get the margin to 45-42 midway through the second. Gee tied it with a layup, Anthony Parker hit a 3 and Jamison scored four more points during a 23-8 run that gave Cleveland a 55-49 lead.
"It wasn't really forced, it came natural and I was able to get quality shots," Jamison said.
Harrington had 12 points off the bench to lead Denver in the first half.
- NBA Commissioner David Stern attended the game. Stern, who is in Colorado for a ski vacation, spoke informally with the media before the game. He said the trade last season that sent Carmelo Anthony from Denver to New York has been good for both teams.
- Irving had eight assists and five rebounds. It's the fourth time this season he has had at least 15 points, five assists and five rebounds.
- The Nuggets are now 9-1 against the Eastern Conference.
- Nuggets G Rudy Fernandez (lower back strain) missed his ninth straight game and F Kosta Koufas (strained left knee) missed his third in a row.