CHICAGO (AP) -- Erick Aybar hit a tying home run in the sixth inning, Luis Torrens walked with the bases loaded against Koji Uehara in the eighth and the San Diego Padres stopped a three-game losing streak by beating the Chicago Cubs 3-2 on Wednesday.
Chicago rookie Ian Happ hit a two-run homer in the fourth against reliever Craig Stammen, going deep for the second straight game and third time in four.
Jose Pirella started the comeback with an RBI single in the fifth off Eddie Butler, and Aybar tied the score against Brian Duensing.
Uehara (2-4), the fifth of six Cubs relievers, replaced Pedro Strop starting the eighth and allowed singles to Wil Myers leading off and Cory Spangenberg with one out. Erick Aybar was intentionally walked, loading the bases, Matt Szczur fouled out and Torrens took a 3-1 fastball that sailed inside.
Phil Maton (1-0), the third of five Padres relievers, pitched a scoreless seventh for his first major league win, and Brandon Maurer got two outs for his 13th save in 15 chances.
Diaz, making his third major league start, left with one out in the third inning because of a right forearm strain. He allowed one hit and a walk, then was replaced by Stammen.
Cubs starter Eddie Butler gave up one run, five hits and three walks in four-plus innings, leaving after Stammen doubled leading off the fifth and scored on Pirella's single.
Chicago's Anthony Rizzo went 0 for 4, stopping a career-high, 14-game hitting streak. He failed to reach base in his opening at-bat for the first time since being moved the leadoff spot eight games earlier.
Nolan Patrick, a projected No. 1 pick on Friday at the NHL draft, threw out the ceremonial first pitch. He was joined two other top prospects, Casey Mittelstadt and Gabriel Vilardi, in a pre-game ceremony.
Padres: 2B Yangervis Solarte (strained left oblique) is "probably a day away from heading to the DL," manager Andy Green said before the game. The cleanup hitter was removed from Tuesday's game in the first inning. … C Austin Hedges (bruised thigh), hit hard by Rizzo in a collision at the plate on Monday, was available to pinch hit but did not play.
Cubs: OF/C Kyle Schwarber went 0 for 3, dropping his average to .171. He missed Tuesday's game, a day after fouling a pitch off his right ankle on Monday. … OF Jason Heyward missed his third game after scraping his left hand sliding in an attempt to catch a foul ball on Sunday.
Padres: Rookie RHP Dinelson Lamet (2-2, 7.50) starts Friday's homestand opener against Detroit and RHP Michael Fulmer (6-5, 3.45), the AL Rookie of the Year. Lamet struck out 12 at Milwaukee on Saturday.
Cubs: RHP Jake Arrieta (6-5, 4.64) is to open an 11-game tip Friday at Miami, which starts LHP Jeff Locke (0-2, 4.58). Arrieta has failed to finish the fifth inning in his last two starts, allowing seven runs, nine hits and five walks in nine innings.