Ross struck out a career-high 11, and the light-hitting Padres broke out for a season-best nine runs in the sixth inning in a 13-3 rout of the Cubs on Thursday night.
Ross (9-10) allowed one run, five hits and one walk in six innings to reach a career high in wins. He went 3-2 in five July starts, but gave up just four earned runs in 35 innings.
''The power fastball-slider combination was there,'' Padres manager Bud Black said. `It's devastating.''
Ross relied on those pitches when he needed to.
''That was my go-to combo,'' Ross said. ''I'm just trying to get better, and tonight I had my sinker back a little bit and got positive results.''
Rene Rivera had three hits, including a home run, and drove in three runs. Will Venable had three hits and two RBIs, and Alexi Amarista and Chris Nelson also drove in two runs apiece with singles in the sixth-inning outburst that gave the Padres their highest scoring output this season.
''We started the season struggling at the plate and now we've been hitting better,'' Rivera said. ''We're scoring more runs since the first half of the season. I think it was time to do it.''
The Padres, who finished with 14 hits, delivered an encore on an 8-3 trouncing of the Cubs on Wednesday.
San Diego led 3-1 entering the sixth, but after the first two Padres reached base, Cubs starter Edwin Jackson (5-11) was pulled because of cramping in his right hand and was replaced by Brian Schlitter.
''I felt pretty good and then all of a sudden you go and you can't throw a fastball for a strike with my finger cramping,'' Jackson said.
The first nine Padres reached as San Diego, which carried an MLB-worst .215 batting average into the game, sent 15 men to the plate.
The Padres beat Jackson and the Cubs 11-1 on May 23 in their previous best offensive output.
''I thought we tried everything we could to minimize the damage, but it ended up kind of escalating,'' Cubs manager Rick Renteria said. ''It seemed like no matter who we used today it kept getting away. It kind of steamrolled.''
Jackson dropped his fourth straight decision over six starts, allowing five runs and seven hits. He hasn't won since June 20 against Pittsburgh.
He was followed by five relievers as Chicago lost for the 13th time in 16 games.
The Padres tagged Jackson with two quick runs with two outs in the first.
The Cubs cut it to 2-1 in the fourth and had runners on second and third with two outs. But Ross fanned John Baker for his eighth strikeout to end the threat.
Rivera's solo shot to lead off the fifth made it 3-1.
National League home run leader Anthony Rizzo swung and missed a 3-2 pitch in the dirt with two out in the fifth to apparently end the inning. But the ball got away from Rivera, and Rizzo reached first with Arismendy Alcantara taking third.
Black asked for a review, claiming the batted ball struck Rizzo, but the play was upheld.
NOTES: The Padres plan to recall RHP Jesse Hahn and start him in Atlanta on Friday against LHP Alex Wood (7-7). Hahn, 24, is 5-2 in seven starts with San Diego this year. ... Padres rookie Jake Goebbert, a former Northwestern University standout, started in left field after sitting out Wednesday. Goebbert's parents own a pumpkin farm in nearby Hampshire, Illinois, and he had a large group of friends and relatives in the stands. ... Cubs C Welington Castillo was rested after drawing boos during Wednesday's loss when he didn't run out a comebacker. ... Cubs LHP Travis Wood (7-9,) will face St. Louis' RHP Joe Kelly (2-1) on Friday.