Two of the teams that began the season in the top 15 will square off in the semifinals of the Pac-12 Tournament when the top-seed UCLA Bruins battle the fourth-seed Arizona Wildcats at MGM Grand Garden Arena on Friday night.

The winner of this matchup will advance to play either 10th-seed Utah or third-seed Oregon in Saturday's title game.

Arizona held off the feisty fifth-seed Colorado in its quarterfinal matchup on Thursday with a 79-69 victory. The win was the second straight for the Wildcats who let their chances at the No. 1 seed slip away with a pair of two- game slides over the last nine games of the regular season. Arizona is 24-8 overall and trying to add to its league-leading conference Tournament title collection which stands at four currently.

UCLA didn't have an easy go of it in its matchup with ninth-seed Arizona State in the quarterfinals. The Bruins trailed by as many as 15 points in the contest but managed to come back and edge the Sun Devils, 80-75. The win was the sixth in the last seven games for the Bruins who are the top seed in the tournament for the first time since 2008 when they made it all the way to the Final Four.

It was the Bruins that had the upper hand during the regular season against the Wildcats. UCLA posted wins both at the McKale Center and Pauley Pavilion to increase its all-time series lead to 51-37.

After going down 2-0 in the early going, Arizona took a 4-2 lead at the 18:45 mark and never trailed again versus Colorado. The Wildcats' advantage grew to as many as 14 points but was whittled to just two with a little more than a minute to play. However a Nick Johnson jumper and a 6-of-6 effort from the free-throw line in the last 30 seconds sealed the win for the Wildcats.

Johnson (11.6 ppg, 3.6 apg) had the hot hand for Arizona in the quarterfinals as he finished tied with a game-high 18 points on a 6-of-7 shooting effort. Mark Lyons (14.9 ppg, 3.0 apg) has been fearless in taking shots after transferring from Xavier this year and showed it yet again on Thursday. Lyons netted 14 points and had a crucial 3-pointer falling away in the corner in the waning minutes. Solomon Hill (13.6 ppg, 5.2 rpg) put up a normal performance by netting 13 points to go with seven rebounds and four assists. Arizona is one of the better offensive teams in the conference, netting 73.4 points per game and shooting 45 percent from the field, both ranked second in the Pac-12.

The Bruins just kept chipping away in the second half against the Sun Devil. The crucial portion of the contest was when UCLA went on a 13-2 run to take its first lead since early in the first period, 67-66. The Bruins' efforts on the interior loomed large as they outscored the Sun Devils, 38-28, in the paint.

Five different players scored in double figures for the Bruins on Thursday led by 20 points from Larry Drew II (7.7 ppg, 7.6 apg), who knocked down 8-of-10 shots from the field. The North Carolina transfer is normally a distributor first for the Bruins after leading the Pac-12 in assists during the regular season. Co-Pac-12 Freshman of the Year Shabazz Muhammad (18.2 ppg, 5.2 rpg) had 16 points and nearly had a double-double on Thursday to keep his impressive rookie campaign going. Also filling up the basket for the Bruins, who lead the Pac-12 in most offensive categories, are Jordan Adams (15.0 ppg) and the versatile Kyle Anderson (9.7 ppg, 8.8 rpg, 3.6 apg).