Padres, Up by Seven, Collapse : Baseball: Houston uses singles attack to overcome 9-2 deficit and win, 12-9.

SAN DIEGO —  They lost?

The Padres? They didn’t beat Houston Tuesday night?

But they led by seven runs. And Fred McGriff hit a grand slam. And they had beaten Houston eight consecutive times in San Diego. And . . . they lost?

In one of the more implausible games of the season, the Padres, pennant contenders wanna-be, handed a decision to Houston, 12-9, in front of 12,688 in San Diego Jack Murphy Stadium.

It was their most heartbreaking, gut-wrenching game of the season. Until Tuesday, the Padres’ biggest blown lead this season was four runs. The most runs they scored in a defeat this year was seven.

That is, until Tuesday, when they led 9-2 at the end of the fourth.

What are you supposed to do after blowing that? Bruce Hurst walked into the clubhouse with a scowl on his face. Tony Gwynn sat alone, silently stripping off his socks. General Manager Joe McIlvaine paced around the clubhouse with his hands deep into his pockets.

Manager Greg Riddoch, meanwhile, sat with his feet up on his desk and his hands clasped together behind his head.

Houston ripped out his team’s guts, and now it was time to dissect what went wrong.

“It stunk,” Riddoch said.

He paused, and then referred to the disastrous seventh inning, when Houston scored five runs and went ahead, 10-9.

“You’d think that one of six ground balls would have gone at us,” he said. “Ground ball in the hole. Ground ball in the hole. Ground ball in the hole. Ground ball in the hole.

“We’ve just got to get one or two to get a double play and get out of the inning. The bottom line for pitchers is to get ground balls. We got them; we just didn’t get any leather on them.”

Things were certainly fine in the beginning. The Padres trailed midway through the second inning, 2-0, but immediately began a comeback.

Benito Santiago homered in the bottom of the second to make it 2-1. Tim Teufel homered to lead off the third and make it 2-2.

Later in the third, McGriff crashed a grand slam over the right-center field fence. By the end of the third, the Padres led, 6-2.

It was McGriff’s third home run in two nights, and it was his second career grand slam. His other came for Toronto at Seattle on July 21, 1989.

It was also the Padres’ second grand slam of the season. Teufel hit the other Aug. 2 at Atlanta.

The Padres got three more in the fourth and led, 9-2.

And according to the scoreboard, the Dodgers were trailing Cincinnati by a run. Was that a pennant race looming in the distance?

The Padres quickly got their answer. Houston scored three in the sixth when Luis Gonzalez homered off of Benes.

Then came the seventh, and all of the ground balls of which Riddoch spoke.

Andujar Cedeno and Casey Candaele led off with singles.

Out came Padre starter Andy Benes; in came Mike Maddux.

Pinch-hitter Javier Ortiz singled, and Cedeno scored. Center fielder Steve Finley singled, and Candaele scored.

After catcher Craig Biggio struck out, first baseman Jeff Bagwell hit a hard shot toward third that Jack Howell perhaps could have had to start an inning-ending double play. It was a difficult play and the ball skipped, bounded off Howell’s glove and into right field. It was ruled a single, and Ortiz scored.

Out came Maddux (4-2); in came Rich Rodriguez.

Gonzalez singled and Finley scored. Third baseman Ken Caminiti was intentionally walked.

Out came Rodriguez; in came Jose Melendez.

Pinch-hitter Jose Tolentino flied to the warning track in center, and Bagwell scored.

Up stepped Cedeno again, and Houston mercifully attempted a double steal. Gonzalez was caught at the plate, and the inning ended.

The guilty parties: Benes, in six-plus innings, allowed seven runs on six hits. In one-third of an inning, Maddux gave up three runs and three hits. Rodriguez pitched to two batters and allowed one hit. And Melendez, in 2 2/3 innings, gave up two runs, two hits and two walks.

“There have been a lot of games throughout the year that we could have won or should have won,” McGriff said. “You can’t really say one game. It’s been a lot of games.”

Someone asked Riddoch if this was the Padres’ most devastating loss of the year.

“I think it was No. 4,” he said sarcastically. “It was a tough loss. I haven’t ranked them in order yet.”

He paused, and then spoke again. Softly.

“We haven’t squandered one like that.”