Arenas, a 6-foot-3, sophomore guard from North Hollywood, Calif., earned the honor after averaging 28.5 points and shooting 17-of-27 (.630) from the field in a pair of games last week.
He opened the week with a career-high 30 points in an overtime loss at UCLA on 9-of-18 shooting, including 4-of-7 from three-point range. He scored 25 of his 30 points in the second half as UA erased a 13-point second-half deficit. He added four rebounds, two assists, and equaled a season high with three steals.
Arenas followed that up with an efficient 27-point effort in Saturday's win at USC. He connected on 8-of-9 shots from the floor, including 5-of-5 from behind the arc and 6-of-6 from the line. He also added five assists. For the week, Arenas was 9-of-12 (75.0) from three-point range.
It is the second time this season that Arenas has been so honored by the league office. He is one of only two Pac-10 players to win the award twice this season. It is also the 52nd time an Arizona player has been named Pac-10 Player of the Week.
Arenas and the eighth-ranked Wildcats currently have an 18-7 record (10-3 Pac-10). The squad will next be in action on Wednesday, Feb. 21, at Arizona State. Tip-off is scheduled for 8:30 p.m. MST and will be televised on Fox Sports Net.