Milwaukee rookie Yi Jianlian started for the first time in the NBA and scored 13 points in 28 minutes. He also had eight of the Bucks' 30 turnovers. Mo Williams, who signed a six-year, $51.5 million contract in the summer, led the Bucks with 22 points.
Brewer only played in 56 of Utah's 82 games as a rookie last season, averaging 4.6 points, but has led the Jazz in scoring in each of their three exhibition games.
"Ronnie has played well from the beginning," Utah coach Jerry Sloan said. "I thought he had a very good training camp. He's been a lot more focused on what he is doing."
The 6-foot-7 guard scored Utah's first seven points of the fourth quarter, then gave his team the lead for good at 74-73 on a pair of free throws with 6:47 left. He then led a fast break that resulted in a three-point play for Ronnie Price, extending the lead to 77-73.
"I'm just more relaxed out there and trying to play solid basketball," Brewer said. "Guys are looking for me when I come off screens."
Milwaukee managed only a field goal by Royal Ivey during Utah's decisive 18-2 fourth-quarter run.
Yi grabbed the opening tip from Andrew Bogut, but had four turnovers in the first quarter. He missed his first two field-goal attempts, but then made five consecutive shots and has impressed his teammates with his quickness running the floor.
Early in the third quarter, Williams led a fast break and could have made an easy layup, but instead rewarded the 7-footer's hustle by feeding him for a dunk.
"I see a big guy running that hard, why would I lay it up?" Williams asked rhetorically. "He's running the floor and I need him to get going. He's my pick-and-pop guy. I want to get him going and get him in a good rhythm."
Michael Redd, Milwaukee's leading scorer last season, played 23 minutes and scored eight points.
Morris Almond, Utah's first-round draft choice from Rice, also started his first game in the NBA, but missed all six of his shots and was held scoreless in 22 minutes.
The Bucks and Jazz have split a pair of preseason games.
Utah played without Carlos Boozer (personal reasons) and Matt Harpring (right knee, left ankle rehab). Milwaukee coach Larry Krystkowiak chose not to play forward Bobby Simmons, who missed last season while undergoing two leg surgeries.