Arizona (15-5, 5-3 Pac-10) snapped three-game losing streak, their longest since the 1995-96 season, and knocked the Ducks (12-6, 5-3) out of first place in the Pac-10 Conference.
The Wildcats took a 9-2 lead in the first four minutes behind six points from Bristol and extended the margin to 17-4 with 12 minutes left in the half.
Oregon rallied behind four first-half 3-pointers from Jamie Craighead and went on a 30-23 run to cut the lead to 40-34 at the break.
The Ducks took a quick 41-40 lead on Jenny Mowe's lay-up with 18:28 left in the game, but with 15 second-half points Pickney Arizona outscored Oregon 48-35 the rest of the way.
LaKeisha Taylor added 15 points for the Wildcats, and Krista Warren had 11.
Craighead finished with 21 points and a career-high seven 3-pointers. Angelina Wolvert added 18 points; Lindsey Dion had 12 and Jenny Mowe had 10.