Tim Stauffer had a tough time figuring this one out.

The San Diego starter who doesn't give up many home runs was at the center of a record-book night Saturday, allowing five in the first three innings. The Cincinnati Reds hit seven in all — matching the Padres' record — in a 13-1 victory that San Diego immediately tried to forget.

"Just one of those games that it's really hard to explain," Stauffer said.

Miguel Cairo and Ryan Hanigan each homered twice in Cincinnati's biggest home run splurge of the season. The Reds won for the fourth time in a row, one shy of their season high.

Surprising stuff all around.

"We don't have those," manager Bud Black said. "Over 162 games, you're going to have 'em, but the Padres don't have many of them at all. Our pitching is just too good."

Stauffer (7-9) tied Woody Williams' club record for most homers allowed in a game. Stauffer gave up three — his previous career high — in a 9-8 loss to the Mets on Monday. The eight homers allowed in consecutive starts also is a Padres record.

He's the first Padres pitcher to allow at least three homers in consecutive starts since David Wells in 2007. He's the fourth major leaguer to allow five in a game this season, joining Sean O'Sullivan, CC Sabathia and Carlos Zambrano.

"You never expect to be embarrassed out there, and that's what happened today," Stauffer said.

Reds starter Homer Bailey (7-5) gave up six hits in seven innings, including Kyle Blanks' homer.

One of the major leagues' most homer-friendly ballparks was at its most gracious. All 14 runs scored off homers. The eight combined homers matched Great American's record for a game.

Joey Votto hit a solo homer in the first inning, latching onto a below-the-knees fastball from Stauffer. After Jay Bruce walked, Cairo homered for a 3-0 lead.

Todd Frazier led off the second with a homer, and the Reds sent eight batters to the plate for five runs in the third. Bruce hit a two-run shot — his fourth homer in the last six games — and Hanigan completed the rally with a three-run drive that left Stauffer rattled.

The right-hander dropped the baseball that catcher Nick Hundley tossed to the mound while Hanigan rounded the bases. Second baseman Orlando Hudson then jogged to the mound for a pep talk. Stauffer retired Bailey to end the inning and his appearance.

It was a stunning turnaround for Stauffer, who had been at his best in his last dozen starts, putting up a 2.25 ERA.

"Tonight I didn't have much to work with," Stauffer said. "Everything was a little flat."

Black and the coaches will look at video of Stauffer's last two starts to see if anything has changed in his delivery.

"It just snowballed on Tim a little bit," Black said.

Cairo hit another two-run shot off Anthony Bass for his first multihomer game. Hanigan had a two-run shot in the eighth against Joe Thatcher for his second career multihomer game.

It was the fourth time San Diego gave up seven homers in a game, the last time on Sept. 18, 2006, at Dodger Stadium. All four of those games came on the road.

The last time Cincinnati homered seven times was July 4, 2010, at Wrigley Field.

NOTES: The Padres wrap up their 10-game trip to New York, Pittsburgh and Cincinnati on Sunday. They're 5-4 so far. ... The Reds will try for their first sweep of the Padres in Cincinnati since they took three straight in August 2002, the final season at Cinergy Field. ... LHP Wade LeBlanc will make his sixth start of the season for San Diego on Sunday. He hasn't given up more than three earned runs in any start so far. ... Reds 2B Brandon Phillips was out of the lineup for the fourth straight game because of a sore left elbow, hit by a pitch last Tuesday. He took ground balls and is expected back on Sunday. ... LHP Dontrelle Willis tries for his elusive first win for Cincinnati on Sunday. Willis is 0-2 in six starts. The bullpen has blown three saves behind him. ... Willis has hit safely in all six starts. It's the longest hitting streak by a Reds pitcher since Jose Rijo hit in eight straight in 1993.