SAN JOSE, Calif. - When push came to shove this season, a Cal basketball team without much innate aggression learned to give as much as it takes.

Rediscovering their physical side after back-to-back defeats will be crucial when the Golden Bears open NCAA tournament play Thursday afternoon against UNLV at HP Pavilion.

"We have to be the aggressor from the beginning," sophomore forward David Kravish said. "That's how we went on the run that got us to this point. Whether they were bigger, faster or could shoot better than us, we kept them moving backward while we kept moving forward."

The lesson of aggression was not easily absorbed by the Bears (20-11), who lost, 76-75, at home to the Runnin' Rebels (25-9) on Dec. 9 in Berkeley when Quintrell Thomas converted an air ball into the game-winning putback.

Strong and fast, UNLV will test Cal with defensive pressure and aggressive offensive rebounding. The Rebels boast 250 steals and 197 blocked shots and will work hard to impose their will.

"I don't think we have physical kids by nature," Cal coach Mike Montgomery said. "It's hard for them to change the way they are naturally."

That translated at times to playing soft, especially on defense.

Recalling early losses to Wisconsin and Colorado in which they allowed 81 points each, Kravish said, "It was obvious we needed a mentality change. The body language was bad, we were getting beat everywhere on defense."

But during an impressive seven-game stretch through most of February, the Bears played with a defensive toughness that shot them from near irrelevance in the Pac-12 to the brink of a conference title.

Cal's run of seven straight victories began with a 77-69 win at then-No. 7 Arizona, and other victims included UCLA and Oregon. The Bears held their foes to 56.7 points per game and 33.5 percent shooting during the run.

The Feb. 17 home game against USC got national headlines when Montgomery shoved star player Allen Crabbe during a timeout. The Bears, down by as many as 15 points in the second half, then rallied behind Crabbe for a 76-68 win.

But Kravish said the turnaround actually began more than two weeks before, with the Bears trailing by 12 points early in the second half against Oregon State and at risk of dropping to 3-5 in Pac-12 play.

Cal held the Beavers to 33 percent shooting in the second half to win, then put a serious defensive squeeze on Oregon in a 58-54 home win.

"That really clued us in to what we had to do," Kravish said.

The Rebels' big front line, featuring 6-foot-8, 240-pound freshman Anthony Bennett, will challenge Cal.

"Vegas ... they've just got a lot of players and big players. And Anthony Bennett is special," said Oregon coach Dana Altman, whose team also played the Rebels this season. "We spent a lot of time chasing him around. He's proven to everybody he's a special, special player."

A 6-foot-8, 240-pounder with a midrange game and the ability to punish defenders inside, Bennett averages 16.1 points and 8.1 rebounds. He's projected as an NBA draft lottery pick this spring should he decide to leave school.

Bennett might already know what he's planning to do, but he's not saying.

"It's a hard decision," he said. "I like the city of Vegas, I like the fans, the coaching staff is great, teammates. I'm just going to take that into consideration when I make my decision."