CINCINNATI -- Greg Maddux has never gone so long without a win.

The 350-game winner had another teasing day on the mound Wednesday, watching his lead vanish one pitch after he left the game. Edwin Encarnacion hit a two-run homer that put Cincinnati ahead, and Adam Dunn added a grand slam that let the Reds pull away to a 9-5 victory over the San Diego Padres.

Again, nothing to show for Maddux.

"I appreciate the fact that I'm still playing," the 42-year-old pitcher said. "I appreciate the fact that I still play good enough to win. I haven't won, but I feel like I've been playing (good). And I do appreciate that."

He hasn't won since May 10, going 14 starts without a victory. He was thwarted again Wednesday with an assist by the Padres' defense and bullpen.

Maddux left the game with a 3-2 lead in the sixth after giving up an unearned run set up by a fielding error. Encarnacion hit the first pitch by Cla Meredith (0-3) for a two-run homer to put the Reds ahead, dooming Maddux to another empty outing. He's 0-5 with nine no-decisions and a 4.54 ERA since his last victory.

While Maddux took it with equanimity, those around him regretted that they weren't more helpful.

"I don't know how many synonyms there are for frustrating," manager Bud Black said. "I'm sure there's a few. But he's pitched great. He plays the game. It's just unfortunate that we dropped the ball that leads to three runs."

Bronson Arroyo (9-7) won his fifth consecutive start by holding the Padres to three runs in seven innings. It's the longest consecutive-win streak by a Cincinnati pitcher since Steve Parris won seven in a row in 2000.

San Diego loaded the bases off Todd Coffey in the ninth. Struggling closer Francisco Cordero came on and walked Jody Gerut to force in a run with two outs, then retired pinch-hitter Scott Hairston on a fly ball to the edge of the warning track in left field for his 21st save in 27 chances.

The Reds hit three homers in all, including Dunn's eighth career grand slam in the seventh inning off left-hander Joe Thatcher that made it 9-3.

The Padres lost two of three in the series and traded left-hander Randy Wolf to Houston on Tuesday, underscoring their hopeless situation. San Diego has lost eight of nine.

The final game of the series featured a high-profile matchup: Maddux, who has 350 career wins and four Cy Young awards, against Ken Griffey Jr., who has 606 homers and All-Century honors. Maddux held Griffey to a harmless single in three at-bats.

Javier Valentin was another matter. Valentin had a single and a solo homer, leaving him 11-for-28 in his career with five homers off Maddux.

"I don't know, maybe it's magic," Valentin said. "I just let him pitch. We've got a lot of young guys who like to swing the bat. They're free swingers, but with a pitcher like that, you've got to let him pitch. I know sooner or later, I'm going to get a pitch to hit, and you can't miss it."

Still, the right-hander was on track to get his breakthrough win until the defense let him down. Maddux caught Brandon Phillips straying too far off second base with one out in the sixth, but shortstop Khalil Greene dropped the ball during a rundown, allowing Phillips to take third.

When Dunn followed with a run-scoring single, Maddux was finished and the Reds were delighted.

"He was pitching masterfully," manager Dusty Baker said. "That was the Maddux I know -- low pitch count, nothing but squibbers, and nothing up."

One pitch after Maddux left, his chance for a win was gone, too. Encarnacion's homer off Meredith was his sixth in the last 11 games.

Gerut opened the game with a homer off Arroyo, and Kevin Kouzmanoff hit a two-run shot for a 3-1 lead in the sixth. Kouzmanoff is 6-for-9 career off Arroyo.

Notes

• The Padres called up LHP Wil Ledezma from Triple-A Portland to take Wolf's roster spot. After the game, they optioned Thatcher to Portland. They will make a corresponding move on Thursday.
• Gerut's leadoff homer was his first of his career and the fourth this season by the Padres.
• Maddux is 24-16 against the Reds in 55 career starts. He hasn't lost to them since Sept. 12, 2005, going 6-0 with two no-decisions since.
• RHP Josh Fogg will miss his scheduled start Friday. Fogg was hit in the face by a batted ball during batting practice Tuesday night. He needed 30 stitches for a split upper lip.
• Reds rookie Jay Bruce extended his hitting streak to a career-high 12 games.