PITTSBURGH -- Edinson Volquez got a little extra rest and some early run support. It was all he needed to end a post All-Star break slump.
Volquez (14-5) had just two perfect innings but limited the Pirates to one run and five hits in 6 2/3 innings.
"Edinson threw a great game, that's where it starts," Cincinnati manager Dusty Baker said. "He gave us all we needed."
The All-Star right-hander entered 1-2 with a 6.64 ERA in four starts since the break. He was originally scheduled to start Sunday against Houston, but was pushed back to Tuesday when Aaron Harang came off the disabled list.
Did the two days help?
"It can never hurt, especially this time of the year," Baker said. "He was throwing strikes. He was a little bit wilder tonight, so maybe he needs to just be a little wild. It was an outstanding performance from him."
Brandon Phillips and Javier Valentin supplied the power with Dunn gone, each hitting a home run to help Cincinnati end a season-worst six-game skid. Corey Patterson had two hits and two RBI.
Phillips hit a two-out, two-run shot in the first off Jeff Karstens (2-1), who tossed 15 scoreless innings in his first two starts after he was acquired from the New York Yankees. Valentin went deep in the fourth, and Patterson had run-scoring hits in the sixth and eighth.
"Brandon got us on the board," Baker said. "That's big against a guy who's been dealing like that. We got on him early."
Phillips' 18th homer provided a big boost to Volquez, who has a 0.77 ERA in 11 2/3 innings at PNC Park this season.
"It's all about the runs," Volquez said. "We took the lead first, and I got more confident on the mound."
Karstens allowed four runs, three earned, and seven hits in seven innings.
Karstens, Brandon Moss and Andy LaRoche, all recently acquired in trades, each played their first home game at PNC Park. LaRoche had an RBI double in the fourth.
Karstens said he had trouble initially adjusting to the mound.
"I didn't feel too comfortable out there," he said. "I felt out of whack. It wasn't until the second or third inning that I got more acclimated."
Doug Mientkiewicz, who scored on LaRoche's hit, ended two possible Pittsburgh rallies. He grounded out to first with runners on second and third in the fifth and again in the seventh with the bases loaded.
Pittsburgh manager John Russell credited Volquez for pitching out of the jams.
"When he got in trouble, he threw the ball well," Russell said. "Our opportunities tonight seem to come with two outs. When things got dicey, he stepped up and made some good pitches."
Chris Gomez and Nate McLouth had two hits apiece for Pittsburgh.
Cincinnati traded Dunn to Arizona on Monday for a minor leaguer and two players to be named. ... RHP Tanner Scheppers, Pittsburgh's second-round draft choice out of Fresno State, threw in the bullpen before the game. Scheppers, who is recovering from a shoulder injury, is unsigned. ... Pirates closer Matt Capps, on the DL with right shoulder bursitis, pitched a scoreless inning and struck out two in his first rehab appearance with Double-A Altoona. ... Pirates 1B Adam LaRoche, on the disabled list with a strained rib cage, went 2-for-4 in the second game of a rehab stint with Class A Hickory. ... Pirates SS Jack Wilson and 2B Freddy Sanchez, each hampered by minor right shoulder problems, were not in the starting lineup. Sanchez grounded out as a pinch hitter in the ninth. ... Cincinnati improved to 2-9 since trading Ken Griffey Jr. to the Chicago White Sox on July 31. ... Valentin has hit safely in 12 of his 13 starts. ... Two Cincinnati players collected their first major league hits. Chris Dickerson, called up before the game, doubled in the seventh and pinch-hitter Adam Rosales singled in the ninth.