The win—Reno's fifth-straight overall and second-consecutive walk-off victory—reduced the Aces' magic number to five with 14 games to play. Reno extended its lead in the Pacific North division to 9.5 games over Tacoma, after entering the series with a 5.5 game lead.
The Aces led 4-3 entering the ninth, but Tacoma plated a single run off Kam Mickolio to tie the score at four heading into the bottom of the frame. In the home half of the ninth, Hallberg started the rally with a single to left, setting the stage for Frey. After left-hander Cesar Jimenez entered the game to face Frey, the Aces center-fielder ended the contest with a line-drive triple off the right-field wall, plating Hallberg and completing the sweep.
Wes Roemer gave the Aces a quality start, holding Tacoma to three runs on seven hits in 7.1 innings of work. Mickolio (3-3) picked up the win after allowing a run on two hits over the game's final 1.2 frames.
The loss fell to Rainiers' reliever Steve Delabar (0-1), who surrendered one run in 2.1 innings. Chris Seddon started for Tacoma, giving up four earned runs in six innings while taking a no-decision.
Frey and Hallberg finished with a pair of hits each, while Cole Gillespie and Andy Tracy drove in two runs apiece. Tracy's two-run double in the sixth flipped a 3-2 deficit into a 4-3 Aces lead, while Gillespie recorded his league-leading 16th triple in the first.
Reno now hits the road for a six-game, five-day road trip in Tucson, beginning Wednesday evening. In the opener, RHP Barry Enright (8-4, 4.95 ERA) will toe the slab for the Aces, while the Padres will counter with RHP Jeremy Hefner (8-7, 5.40 ERA). First pitch is set for 7 p.m.