LOS ANGELES – The drivers seat in the Pac-10 conference race is no longer solely occupied by the Arizona Wildcats.

Reeves Nelson and the UCLA Bruins barged themselves into position, meeting little resistance in a 71-49 victory over the Wildcats at Pauley Pavilion that put the teams in a first-place tie entering the final weekend of the season.

Nelson was dominant in the post, collecting 27 points and 16 rebounds, and Josh Smith added another 17 points inside for the Bruins.

Arizona, which shot just 31.1 percent from the field, was led by Derrick Williams, who had 15 points and seven rebounds.

It was the first time Arizona has lost consecutive games all season.

The Bruins pulled into a first-place tie with the Wildcats at 12-4 in Pac-10 play, but UCLA will head to Washington State and Washington for its final regular-season games while Arizona will host Oregon State and Oregon.

Washington will be a game behind the Bruins and Wildcats if the Huskies can beat WSU on Sunday. Arizona, which was rated No. 10 in both national polls last Monday, fell to 23-6 overall. UCLA improved to 21-8 overall.

Aftter they trailed 40-30 at halftime, thanks to a 15-4 UCLA run at the end of the first half, the Wildcats put themselves in a hole they couldn’t recover from in the second.

They failed to score for the first four and a half minutes after halftime, struggling to contain Nelson and Smith inside, and trailed 51-30 by the time Nelson hit a pair of free throws with 15:56 left.

Effectively, UCLA had a 24-4 run over the end of the first and beginning of the second halves.

The Wildcats did recover partially from there with a 10-0 run fueled by three-pointers from Kyle Fogg and Jamelle Horne. The run cut UCLA’s lead to 51-40, but it wasn’t enough.

The Bruins finished the game on another huge run, 12-1.

Nelson had 16 points and 10 rebounds in the first half, leading the Bruins to a 40-30 halftime lead over Arizona.

Just a sophomore who was heavily recruited by the Wildcats early in his high school career, Nelson has already made a habit of having his way with Arizona inside.  He collected 24 points and 10 rebounds against Arizona last month at McKale Center. He also had 19 points and 10 rebounds to lead UCLA to a 75-69 win over Arizona in the Pac-10 Tournament quarterfinals last season.

Overall in three previous games against UA, Nelson averaged 17.6 points and 9.3 rebounds. He missed UA’s 78-73 win at McKale Center last season.

The game stayed within a basket for much of the first half, appearing like the battle for first place that it was, until UCLA finished the first half on a 15-4 run.

The Bruins repeatedly burned the Wildcats inside, making 72 percent of their two-point shots through the first 16 minutes. UCLA finished the half shooting 58.6 percent from the field overall while Arizona shot just 38.5 percent.

Arizona, which was also outrebounded 18-11 by UCLA overall, was led offensively by Williams, who had 13 points.

The Wildcats started off slowly, and didn’t score a field goal until Fogg made a layup with 16:49 left.

But that basket cut UCLA’s lead to 6-3 and Fogg returned for a three-pointer that tied the game at 6-6 and it remained close.