BOULDER - Colorado freshman Xavier Johnson continues to mature and come into his own on the basketball court - and it was never more evident than in the Buffaloes' 81-71 Pac-12 Conference win against California on Sunday.

The 6-6 guard from Los Angeles recorded his first career double-double, scoring a career-high 18 points and grabbing a game-best 12 rebounds. No other CU player collected more than five boards on the night.

"I can't say enough about Xavier Johnson," CU coach Tad Boyle said. "I think you can make a legitimate argument that he was the MVP of today's game offensively."

Johnson had recorded 10 points by intermission, helping the Buffs to a 34-18 halftime lead.

Boyle said Johnson showed more maturity than ever, but that his level of play has been rising throughout the conference season. 

"He played aggressive, he took good shots, and when he drives it and takes it to the rim, he's pretty hard to handle down there," Boyle said.  "Xavier was terrific for a freshman. He's really grown up these past three weeks. Ever since we've started conference play, he's stepped his game up."

Johnson's play, however, while consistently strong against Cal, was far better than his norm. Before Sunday, Johnson had averaged 9.6 points and just 3.6 rebounds per game, shooting 44.7 percent from the field. Sunday, Johnson shot 70 percent from the field (7-for-10) and hit all four of his free throw attempts.

While he did record five turnovers, that number was not an unusual one for the Buffs on Sunday. The Golden Bears forced 20 Buffs turnovers and recorded 16 steals.

Sophomore point guard Askia Booker, however, said that the team's decent scoring helped outweigh some of that sloppiness, especially in the second half .

"A little lackadaisical," Booker said of the team's second-half play. "We didn't get stops when we needed them. But we scored the ball well and we shot almost 60 percent, so I mean, sometimes that's going to make up for our defense."

Johnson and Booker scored a combined 36 points, 44.4 percent of the Buffs' total.

Scoring well is not always enough, though, and Booker said his team won't be satisfied with all aspects of Sunday's game.

"Our philosophy is defense and rebounding, so we have to get better at that," Booker said.

According to that philosophy, Johnson's dozen rebounds against the Golden Bears is an example worth following. His teammates call him the "X-Factor" - and he's living up to that nickname more fully with every game.