BOSTON -- The novelty of playing in Fenway Park wore off quickly for the Giants, who continued to stagger with no signs of stopping.

Their latest setback was Sunday's 9-5 loss to the Boston Red Sox, who swept the three-game Interleague series. Losers of four games in a row and 16 of their last 22, the Giants fell 10 games behind first-place San Diego in the National League West -- a nice, round number in most instances, but not this one.

"This really is tough to swallow. But there's time left and I believe in the guys in here, for sure," said right-hander Matt Morris, who endured his worst game of the season. "As long as we believe in ourselves and try to play the game the right way, we'll see where we are at the end. Right now, it's one thing after the other, whether it's not hitting or a bad start or giving up runs at crucial times -- it seems to snowball."

Barry Bonds' 748th career homer was among the afternoon's few redeeming elements for the Giants, who own a 3-9 Interleague record. Pedro Feliz also homered, a fourth-inning drive onto Landsdowne Street that began San Francisco's mild comeback from a 7-2 deficit. Randy Winn's third-inning RBI double ended the Giants' stretch of 26 consecutive hitless at-bats with runners in scoring position, dating back to last Wednesday.

Winn's hit didn't reverse the Giants' fortunes, however. They finished the game 1-for-9 with runners in scoring position, squandering a bases-loaded, one-out opportunity in the seventh inning when they trailed 8-5. Bengie Molina, one of the team's best clutch hitters, ended the threat by grounding into a double play on reliever Joel Pineiro's first pitch.

"They were fighting the whole game," Giants manager Bruce Bochy said, referring to his club's ability to bring the potential go-ahead run to the plate. "They were grinding it out. That's what you have to do at this point."

Given their current state, the Giants might have to grind until their collective gears are worn smooth. Their schedule gets no easier for the next two weeks. They proceed to Milwaukee for a three-game series against the NL Central-leading Brewers, then return home for a three-game weekend series against the resurgent New York Yankees. Next comes a pair of three-game series against San Diego and Arizona, which will represent a crucial chance for the Giants to reassert themselves within the division.

Conventional wisdom dictates that the Giants' capable starting pitching should keep them competitive. This time, however, Morris became the club's third starter to allow eight runs in a game, joining Barry Zito (April 8 against Los Angeles) and Russ Ortiz (May 1 against Colorado) in that dubious distinction.

The Red Sox settled matters with a five-run third inning as they batted around against Morris (7-4), who lasted only four innings. J.D. Drew coaxed a leadoff walk before first baseman Ryan Klesko fumbled Dustin Pedroia's bunt on a play that was scored a single. David Ortiz doubled in a run and Manny Ramirez's groundout produced another. Kevin Youkilis' RBI single and Mike Lowell's run-scoring double continued the uprising against Morris, who also yielded Doug Mirabelli's two-out RBI single.

Asked if he elevated his pitches too much, Morris replied, "Yeah, you could say that, but as I looked at it, the strike zone was up there, too. Balls down weren't called. The strike zone was probably higher than it should have been. But I picked a bad time to have a bad start. It's really nobody's fault but my own. I wasn't controlling counts, and when I did, I couldn't put anybody away. That's a recipe for disaster. ... I'll take the blame for this one."

Bonds' homer, which left him seven short of Hank Aaron's all-time mark, added a touch of the sublime to the Giants' effort. Fenway Park became the 36th ballpark in which Bonds has homered. Bonds' former Pittsburgh Pirates teammate Tim Wakefield (7-7) joined the record-setting list of pitchers who have yielded home runs to him. Wakefield checked in at No. 441.

But even while Bonds spoke graciously of Boston as he summarized his weekend, he fired a jab -- probably unintentional -- at his home city.

"It's a beautiful ballpark. It's a beautiful city," Bonds said of Fenway and Boston. "We're in San Francisco where streets are a little bit dirty and stuff like that. Being around here, walking around town and going to the park, it's very clean."

Just another sour note during an extremely sour period for the Giants.