SAN FRANCISCO -- When the bottom of the fourth inning rolled around at AT&T Park on Sunday afternoon, Jeff Karstens was working on a tidy no-hitter, Nate McLouth was enjoying his entry into the 20-20 club and the Pittsburgh Pirates still had a chance at avoiding a most ignominious feat.

Cue the deluge.

After an absurd 10-run rally that turned from comic to nearly tragic when McLouth suffered a laceration above his left eyebrow that required six stitches to close, the Giants completed an 11-6 victory that guaranteed Pittsburgh (60-82) a 16th consecutive losing season.

Along with the Philadelphia Phillies of 1933 through 1948, the Pirates now share the record for the longest streak of losing seasons put together by a professional sports franchise.

"Nobody's happy with the record. Nobody's happy with losing," Pirates manager John Russell said. "With the work they're putting in and the things that we're doing, we see a lot of progress. It's just not equaling to wins right now."

It was fitting in one way that the Pirates' streak should be extended against the Giants, the team that lured Barry Bonds away from Pittsburgh after the 1992 season with a six-year, $43.75 million contract that was then the biggest in baseball history. In his absence, the Pirates slipped from 96-66 -- and a third consecutive National League East title -- to 75-87, the first of their 16 years under .500.

"It's easy to take a look at the big picture and say, 'Oh, here we go again, but I think the reality is ... we knew we had a lot of work coming into it," said first-year general manager Neal Huntington, who chose to trade veteran outfielders Jason Bay and Xavier Nady rather than try to build around a shaky foundation. "We feel like we've made some difficult decisions in the short-term that will benefit the organization in the immediate and distant future."

That future was not Sunday, when the Giants, after conceding a 5-0 deficit, sent 14 hitters to the plate in the fourth. Nine of them hammered out hits, and Pittsburgh added a pair of errors for good measure, making half of the 10 runs unearned. Karstens committed an error to let leadoff man Randy Winn get on base, then allowed six straight hits, including doubles by Pablo Sandoval and Travis Ishikawa. Karstens eventually was tagged with eight runs. Reliever T.J. Beam allowed the final two.

How to explain it?

"You can't. You go from no hits to nine hits and 10 runs," Russell said. "They found holes. They hit balls down the line. It was just one of those outings. It's not like [Karstens] threw the ball bad. We just couldn't stop the bleeding."

Stanching blood became a literal problem. Sandoval stroked a sinking line drive into the left-center-field gap with the bases loaded. McLouth, whose stolen base in the third inning made him only the second Pirates player this decade to record 20 steals and 20 home runs in the same season, took off in pursuit, but his dive fell just short.

The ball took one malevolent bounce into McLouth's face, popping the lens out of his sunglasses and driving the frames into his face, causing the gash. McLouth said there was no worry of a concussion or other more serious head injury, but that was about the only positive to come from the inning. It was the first 10-run frame against the Pirates since Aug. 19, 2003, when the St. Louis Cardinals turned the trick.

The Pirates, who knocked Giants starter Jonathan Sanchez from the game after only three innings, did not muster much in the way of a rebuttal until breaking through for a run in the eighth. But it wasn't enough to keep the Phillies from having company among sports' least successful endeavors.

"It's going to be a lot of fun someday," Russell said. "I know the city of Pittsburgh's dying for a winner, and we're going to do everything we can to make sure that happens."