HOUSTON (AP) -- Center field at Enron Field looks like a modern-day death valley, a fence about 3½ feet high atop the grassy knoll, 436 feet from home plate.

Ryan Klesko became the first player to clear it, a shot estimated at 440 shot during San Diego's 8-6, 10-inning win over Houston on Saturday.

"Four-forty? I think it went a lot farther than that," San Diego manager Bruce Bochy said. "That ball would have gone out anywhere."

The ball hit the wall of Union Station, which is behind the fence, at about 25 feet above field level.

"The ball carries well here," Klesko said. "I knew I hit it good when I hit it, but I didn't know I'd hit it that good."

Klesko's two-run homer put San Diego ahead 6-4 in the sixth, but Roger Cedeno retied it with a two-out, two-run single off Donne Wall in the bottom half.

Carlos Hernandez, activated earlier in the day, then hit a two-run double with two outs in the 10th. He had been 0-for-4 with three strikeouts.

"It doesn't matter to me what I did the last time up," Hernandez said. "I don't think about that. I was just looking for a strike. In that situation, I knew the pitcher would be trying to get ahead of me and so I was ready."

Phil Nevin, who was 3-for-5, singled off Yorkis Perez (1-1) opening the 10th, Eric Owen walked with two outs and Hernandez, who strained his right groin April 6, doubled into the gap in left-center.

"I tried to throw a strike, but not a pitch like that," Perez said. "I gave him a pitch he was looking for."

Will Cunnane (1-0) pitched a hitless ninth, and Trevor Hoffman struck out the side in the 10th for his third save.

"The bullpen did a great job today," Bochy said. "This was a good ballgame for us, we came back and got the job done against a very good team."

Al Martin homered and had three hits for San Diego, which outhit the Astros 14-6.

Ken Caminiti and Jeff Bagwell homered for Houston -- Bagwell's sixth in 33 at-bats after he failed to hit one in his first 25. There have been 29 homers in eight games at Enron Field.

Houston's Chris Holt was tagged for six runs and 10 hits in six innings. Holt, who has a 11.51 ERA, leads the league with 26 earned runs allowed. Opponents are hitting .409 against him (36-for-88).

"It's getting tougher and tougher to lose, particularly at home," Houston manager Larry Dierker said after watching his team drop to 2-6 in its new ballpark. "We were sloppy, and we can't afford to be like that."

San Diego's Matt Clement gave up six runs, five hits and four walks in five-plus innings and struck out seven.

Tony Gwynn's sacrifice fly put San Diego ahead in the first, but Clement opened the bottom half with nine straight balls -- walking Craig Biggio and Cedeno -- and Caminiti hit a two-out, two-run homer into the bullpen in right-center.

Clement tied it with a squeeze bunt in the second, but San Diego went ahead 4-2 on Nevin's RBI grounder in the third and Martin's home run off the right-field foul pole in the fifth.

Bagwell's two-run homer, a drive over the railroad tracks above the left-field bleachers, tied it again in the fifth.

Game notes
Houston batters struck out 14 times. ... Astros SS Tim Bogar is hitless in his last 19 at-bats. ... Biggio has hit safely in 13 consecutive games. ... Martin is hitting .150 (3-for-20) against lefties and .390 (23-for-59) against right-handers. ... Nevin is a career .417 (15-for-36) hitter against Houston. ... Cedeno stole four bases tying a career high. ... The crowd of 42,121 was Enron's largest thus far.