Josh Shipp scored 22 points and Mata added a career-high 14 to lead a second-half comeback in an 85-75 victory Thursday night that extended the Bruins' home winning streak to 19 games.
Typically, the sight of Mata stepping to the line induces cringes among UCLA fans. He came into the game averaging 30 percent, worst on the team.
But Mata turned in an 8-of-9 career-best performance.
"Mata's free-throw shooting was a big key," Bruins coach Ben Howland said.
UCLA (24-3, 13-2 Pac-10) completed a season sweep of the Golden Bears (14-13, 6-9), who had won their two previous games at Pauley Pavilion and dominated the first half.
The Bruins stretched their Pac-10 lead to two games over No. 9 Washington State, which lost to 23rd-ranked Oregon 64-59.
Freshman Ryan Anderson led the Bears with 21 points and Omar Wilkes was among three players with 10 each.
Cal led nearly the entire first half, opening with a 14-4 run for its largest lead. The Bears shot 72 percent from the field during that stretch. They finished at 60.5 percent from the floor and 61.5 percent from 3-point range, both season highs.
"Offensively, we attacked UCLA and really broke them down defensively," Cal coach Ben Braun said. "Very few teams do that. We didn't give them easy baskets. That changed late in the half. They got transition baskets that got them back in the game."
The Bruins used a 19-9 run, capped by Luc Richard Mbah a Moute's four straight points, to take their first lead of the game. The teams traded baskets before the halftime buzzer, when UCLA led 35-34.
"Once we caught them, we got our confidence back and got into a groove," Arron Afflalo said. "Cal shot way too high. We have to get back to our defensive basics. We have to rely on our defense to win tough games."
Cal effectively limited guards Afflalo and Darren Collison, but the Bears didn't count on UCLA's big men to carry the offensive load.
Afflalo added 13 points for the Bruins to extend his double-figure scoring streak to 26 games, tops in the Pac-10. But he finished under his team-leading 17.5-point average and Collison had two points on a night when Mata emerged as a reliable free-throw shooter.
He made his first seven free throws before he missed one after being intentionally fouled by Wilkes, whose father, former UCLA star Jamaal Wilkes, was in the crowd.
Mata steadied himself and completed a three-point play near the end of a 14-6 spurt that opened the second half, drawing huge cheers from the crowd.
"It was definitely a great feeling," he said. "It definitely boosted me up. The free throws were the best I've had."
Leading 49-43, UCLA outscored the Bears 25-5, including nine by Shipp, for a 74-48 lead with 7 1/2 minutes remaining.
"Our defense didn't hold up its end of the bargain," Wilkes said. "They're a strong second-half team. They don't give up. Our energy level kind of slid. I looked up and saw it was 70-48 and I thought, `How could that get so out of hand?'"
The Bears reeled off four consecutive 3-pointers, which barely dented their 19-point deficit, but they finished with eight and have 202 on the season, breaking the school record of 198 set in 2002-03.
Fans began filing out with nearly four minutes remaining, and UCLA went to its bench before re-inserting starters Afflalo and Darren Collison with 1 1/2 minutes to go and UCLA ahead by 14.