Hundley was 3 for 4 with three runs batted in for San Diego, which won back-to-back games for the first time since June 20-21.
"There's no doubt there was a struggle," San Diego manager Bud Black said. "We didn't hit and we didn't pitch. Now you're seeing better offensive outputs. You're seeing two good starts from our (pitchers) the last two nights, and that's what it takes.
"It's no secret. It's good to see guys performing like they're capable of."
Ross (1-4), recalled from Triple-A Tucson earlier Tuesday, earned his first win since May 14, 2012. The right-hander, who had lost 12 straight decisions -- including seven as a starter -- gave up just two hits and one run. He struck out six and walked two in a season-high six innings in his first start since April 17.
"I think I was just kind of grinding through it," said Ross, who retired the final nine batters he faced. "I just kept my head up, kept battling trying to get better every time out. It was nice to get that first win in a while."
Milwaukee starter Donovan Hand (0-2) lasted four innings before he left with a bruised right hand after being hit by a pitch. X-rays of his pitching hand were negative, and Hand is listed as day-to-day. He allowed two earned runs and seven hits to go with one strikeout and a walk.
"I went back out for the fourth and everything was still good; a little swelling on the pinky side, but nothing major," Hand said. "Then after the fourth, I just really couldn't grip the ball anymore."
Just before the first pitch, the Brewers announced they traded right-handed reliever Francisco Rodriguez to Baltimore for minor league third baseman Nick Delmonico. Rodriguez is 21st on the career saves list with 304.
On Monday, the Brewers lost 2011 NL MVP Ryan Braun for the rest of the season after he was suspended for violating the Major League Baseball drug program.
"We haven't really hammered the ball for a while," Milwaukee manager Ron Roenicke said. "Some of it is personnel, but I still expect a lot of these guys to have better at-bats. I think they're disappointed in the way they're swinging the bat, and that's a good thing.
"I still expect the guys that we have out there to produce, to scrap and battle and see if we can get some runs across."
Mark Kotsay, who halted an 0-for-25 slump with a single in the second, led off the sixth with a single. Hundley followed with his seventh homer of the season for a 4-1 lead.
Kotsay also singled home a run in the seventh to finish 3 for 4. Hundley added a run-scoring single to make it 6-1 later in the inning.
Venable, Kotsay and Hundley, San Diego's Nos. 6-8 hitters, were a combined 9 for 13 with five RBIs and four runs.
"I know they say hitting is contagious or whatever, but it's just the ability to string together good at-bats," said Venable, who shares the team lead of 12 homers with Carlos Quentin. "Obviously you set out to do that every night. Sometimes it happens and sometimes it doesn't."
Venable's solo homer gave the Padres a 2-1 lead in the fourth.
To make room on the roster for Ross, right-hander Miles Mikolas was optioned to Triple-A Tucson. ... Rodriguez, 31, was 1-1 with a 1.09 ERA in 25 games with Milwaukee this season and was 10 for 10 in save opportunities. Alfredo Figaro will rejoin the team Wednesday to take his roster spot. The right-hander had been on the disabled list with an oblique strain. Delmonico, 21, played for Class-A Frederick this season and had a team-high 13 home runs to go with a .244 batting average. ... Padres pitcher Jason Marquis sustained a complete tear of the ulnar collateral ligament in his right elbow and will soon undergo Tommy John surgery. "As of right now, he plans on pitching again. He's going to give it a go, he's going to rehab and I think he wants to come back and compete," Black said. The 34-year-old Marquis (9-5, 4.05) had lost three straight decisions over six starts. He went on the disabled list Sunday.