Oregon (33-13, 12-8) trailed by four runs with just three innings left, but hung four in the seventh to tie it before winning in extra innings.
"I think that's probably on a short list of as good of comebacks as we've had in a late ball game," Oregon coach George Horton said afterward.
Freshman Austin Grebeck hit a walk-off single to score pinch runner Desmond Santos from third in the tenth. Santos entered the game following a Shaun Chase leadoff single and reached third when A.J. Balta connected on his third hit of the day.
"Coach Was[ikowski] brought it up to me," Grebeck said. "He said my first two at-bats are always not very good, but as the game goes on I usually get better. I guess like the big show."
Grebeck pinch hit for Nick Catalano in the eighth, bunting into a fielder's choice that outed the leadoff runner.
Oregon pitcher Jeff Gold might have been the happiest of all with the rally.
Gold entered the game with a perfect 9-0 record in 11 starts, but left the in the sixth down one run after allowing four of five Wildcats (18-27, 7-16) to reach on base hits. Jordan Spencer granted two more, both credited to Gold, to complete what was a four-run inning, and put his perfect record truly at peril.
After Arizona added a sixth run in the seventh to put Oregon down 6-2, the Ducks scored four runs of their own to knot it at six. The Ducks score all four runs with two outs, led off by a two-run triple from senior Kyle Garlick.
The triple was Garlick's 13th of his career, moving him past George Shaw for tops on the all-time list.
One batter later the Ducks got the necessary punch from an unlikely source. Stephen Packard sent a 2-1 pitch over the right field wall to tie the game at six apiece. It was just his 37th at-bat of the season and his first home run since his freshman year back in 2010.
"That was huge, without that, none of that happens," Grebeck said.
"He was stoked for sure for us to come back and pick him up," Packard said of Gold. "He always backs us up, so today it was cool to do it for him."
Gold allowed five runs on eight hits in and a third innings on the mound.
Tyler Baumgartner batted in shortstop Mark Karaviotis on two occasions for the first two Oregon runs. Karaviotis walked in the third and was hit by pitch in the fifth before Baumgartner singled him in twice, the second time for a 2-1 lead.