LAS VEGAS (AP) — Christian Koloko scored 24 points, Bennedict Mathurin added 20 and No. 2 Arizona held off Stanford 84-80 in the Pac-12 quarterfinals. The top-seeded Wildcats had a hard time shaking the Cardinal in a win late in the regular season and faced a similar issue to open the tournament. Ninth-seeded Stanford beat Arizona State on a buzzer-beater to open the show in Las Vegas on Wednesday and hit Arizona with a flurry of 3-pointers in the encore. Arizona made the biggest plays when it counted most to earn a spot in the semifinals.