Carmelo Anthony topped the Nuggets with a game-high 31 points.
Leading 82-77 after three quarters, the Jazz's (30-21) advantage swelled to nine midway through the fourth period as the game tightened and the intensity increased.
Utah's Raja Bell and Denver's J.R. Smith then began to consistently tangle. And when a high-flying fast-break layup attempt by Bell was met with a hard foul by Smith, Williams instantly responded by charging after Smith and delivering a hard elbow.
"You have to have your teammates' back. And I appreciate that. And I wouldn't expect anything less," said Bell, who immediately found four text messages from friends on his phone after the game that said Williams had clearly stepped up to support his friend.
"It's one of those things where, we have so much of a season left, if we didn't stick together it'd be pretty rough," said Bell, who scored a season-high 20 points. "Jerry [Sloan's] teams stick together usually. Win or lose, you stick together."
Smith received a flagrant two technical foul and was ejected. Williams was hit with a tech.
But Williams had sent a message. And the Jazz who entered the contest having lost eight of their last 10 games while dropping downward in the division standings had made a stand.
Williams said his instant response was a reaction to what he thought was a hard, intentional foul by Smith.
"You've got to have your teammates' back, man," Williams said. "It was a dirty play. I know J.R. I like J.R. But you can't push my teammate out of the air like that."
A highly efficient, streamlined Utah offense produced its best performance in three weeks. In turn, the Jazz improved to 3-2 during their last five contests to move a half-game ahead of Denver (29-21) and back into second place in the division.
Utah received a major boost with the return of Williams. He showed no hangover effects from his injury, running the Jazz's offense with confidence and precision while pushing the tempo whenever possible.
"He did a heck of a job, and we certainly needed everything he gave us," Sloan said.
The Jazz also started strong, despite quickly losing starters Al Jefferson and Gordon Hayward to foul trouble. Utah held 16-10 lead following two quick passes from Williams and Kyrylo Fesenko that resulted in a Paul Millsap layup.
Thirteen combined first-quarter points by Denver's Nene and Chauncey Billups helped the Nuggets climb back to pull ahead 22-18.
But the Jazz tightened up to close the period, and Utah grabbed a 34-30 advantage after Williams buried a 21-foot jump shot with 8 minutes, 33 seconds left in the second quarter.
The in-sync Jazz then took a 50-47 lead into halftime.
A more aggressive Anthony found his mark during the third quarter, though, dropping in 17 points.
But Utah stood strong. Williams found a groove with Bell, while reserve forward C.J. Miles poured in 10 third-quarter points to help give the Jazz an 82-77 advantage heading into the final period.
Fifteen fourth-quarter points from Jefferson, who finished with a team-high 28, then ended Denver's night.
Check The Tribune's Jazz Notes blog at sltrib.com/Blogs/jazznotes for exclusive news, interviews, video and analysis.
R Denver's J.R. Smith receives a Flagrant 2 foul midway through the fourth quarter and is ejected.
Thunder at Jazz
P At EnergySolutions Arena
Tipoff • Saturday, 7 p.m.
TV • FSN Utah
Radio • 1320 AM, 1600 AM, 98.7 FM
Records • Thunder 32-17, Jazz 30-21
Last meeting • Thunder, 115-108 (Nov. 15, 2010)
About the Thunder • Forward Kevin Durant entered a game Friday at Phoenix leading the league in average scoring with 29.3 points per game. … Oklahoma City ranked fifth out of 30 teams in scoring (104.2), led the Northwest Division by 2½ games, and had won three of its last four contests. … Guard Thabo Sefolosha is dealing with a knee injury but played against the Suns.
About the Jazz • Utah entered a road game Friday at Denver having dropped 8 of its last 10 contests. … Forward Andrei Kirilenko (sprained left ankle) did not play against the Nuggets and is day-to-day. … Center Mehmet Okur (strained lower back) is doubtful Saturday night versus the Thunder.