Volquez (8-9) has struggled during long stretches this season, including his past four starts when he had a 13.83 ERA. But on Monday night, Volquez combined his electric stuff with sound mechanics to shut down the Pirates.
"It was closer last start, even though the numbers didn't indicate it," Padres manager Bud Black said. "I think (Monday) was more indicative of what he can do. I still think there is a cleaner game in there for him."
Volquez gave up one run and five hits in 6 2/3 innings as he equaled his season high with the 10 strikeouts. The right-hander walked three and hit a batter.
It was the first time Volquez has pitched past the fourth inning in four starts this month.
"About time," Volquez said with a big smile. "It's a lot of work with my pitching coach (Darren Balsley). I was under control with my mechanics, my delivery was better, my fastball command was better. Everything was better."
The Pirates' loss came on the heels of their 19-inning 6-3 victory at St. Louis on Sunday afternoon.
San Diego, which snapped a five-game losing streak Sunday, has won 16 of 19 against the Pirates. Pittsburgh is a half-game ahead of the Los Angeles Dodgers for the final wild-card berth.
Volquez got help from his bullpen, which pitched 2 1/3 scoreless innings.
Brach's strikeout came after he relieved Volquez in the seventh with runners on first and second. He struck out McCutcheon on a full-count fastball after falling behind 2-0.
"I just reared back and threw it up and at the top of the (strike) zone and he swung through it," Brach said. "You're just trying to make your pitches in that situation."
Thayer pitched the ninth for his seventh save in nine chances and struck out McCutcheon to end the game with a runner on first.
McCutcheon went 1-for-5 as his average dropped to .352.
Correia, who went into the game with a 75-pitch limit, gave up three runs -- two earned -- and seven hits in 4 1/3 innings.
Correia was pulled with runners on first and second after walking Yasmani Grandal with one out in the fifth on his 72nd pitch.
"I just made a couple of bad pitches I wish I could get back," Correia said. "I really feel I threw the ball decently."
Rodriguez, the eighth pitcher used by the Pirates on Sunday, threw two scoreless innings to earn the win.
Correia became the first Pirate since Pascual Perez in 1981 to pitch in relief one day and then start the next day's game.
"The effort was solid and he gave us a chance to win the game," Pittsburgh manager Clint Hurdle said.
The Padres reached Correia, a former teammate, for two runs in the first inning.
Everth Cabrera led off with a double and scored on Venable's single. After a passed ball and groundout, Venable scored on Grandal's infield out.
Cameron Maybin led off the San Diego second with a single, went to second on a sacrifice and to third on Cabrera's infield single. Venable followed with an RBI single for a 3-0 lead.
The Pirates finally reached Volquez when McCutcheon led off with an infield single and went to second on third baseman Chase Headley's throwing error. McCutcheon took third on a groundout and scored on Neil Walker's single.
Rodriguez's next start will be against Milwaukee on Friday at home. ... Correia made his 22nd start out of 24 appearances. ... Correia pitched for San Diego in 2009-2010. ... San Diego's Carlos Quentin was hit by a pitch for the second straight game to run his major league-leading total to 15. It also tied the club record set by Kevin Kouzmanoff in 2008.