Tavarez surrendered two first-inning runs but blanked the Giants over the next six. Zito allowed seven runs (six earned) in 5 1/3 innings while surrendering five hits and walking four.
The Giants, who have lost 14 of their last 20 games, needed a sublime performance to keep up with Boston, owners of the Majors' best record. But San Francisco retreated from the occasion instead of rising to it. Boston had scored two runs or fewer in seven of its previous nine games, but J.D. Drew and rookie Dustin Pedroia, the first two batters in the Red Sox order, led a revival against Zito (6-7). Drew, 0-for-11 in his last four games, went 3-for-4 with three RBIs. Pedroia went 5-for-5 with five RBIs, including a two-run homer.
Although Zito's effort appeared to duplicate other subpar outings -- an excess of walks and pitches thrown combined with a lack of aggressiveness -- he believed that he at least partially followed a path to success, although he's 0-2 with an 8.68 ERA in his last two starts.
Zito, who threw 110 pitches, called Pedroia's homer, which offset the Giants' pair of first-inning runs, a "blatant mistake" on a fastball down the middle. Otherwise, Zito said, "I thought I had decent command most of the night. ... I felt I was aggressive. I felt like came after guys. A lot of balls were where I wanted them to go; we just weren't getting calls. As far as pitch count goes, it was definitely high the last two games, but you have to look inside the game and beyond the stats sometimes and look at how things played out."
Sharing Zito's belief in such scrutiny, Giants manager Bruce Bochy said that he wants to discuss the left-hander's pitching with him "in the next day or so."
Zito sounded agreeable when told of Bochy's intent.
"We'll sit down and see where he's at," Bochy said, expressing confidence in Zito's ability to bounce back.
On Friday, the Giants (30-36) couldn't rebound from Boston's fourth-inning uprising, which resulted from spotty defense as well as shoddy pitching.
With Boston (42-24) leading, 3-2, Zito walked Mike Lowell to open the inning and issued a free pass to Julio Lugo two outs later. Drew doubled in Lowell and Lugo and scored on Pedroia's single.
Those were the inning's bare facts. The fine print revealed more, as the Giants nearly escaped the inning unscathed. As Lugo broke for second base, Mark Sweeney trapped Lowell between third and home. After briefly considering a throw to try to retire Lugo, Sweeney ran across the diamond to make Lowell commit. Lowell dashed back to third and slid in safely when Sweeney uncorked a low, wide throw that forced Pedro Feliz to make a sweeping tag.
"It turned out to be a bad play," Sweeney said, indicating that "not being out there that much" -- it was his third start at first base this season -- might have hampered him.
Said Bochy, "He did everything right. Just at the end he probably held onto it a little too long."
The evening was devoid of drama afterward, which contrasted with the first inning, when Barry Bonds, performing designated-hitter duties, crushed a drive that hooked a few feet outside the right-field foul pole. Bonds thus barely missed his 748th career home run, which would have left him seven short of Hank Aaron's all-time record.
Bochy argued briefly with first-base umpire Charlie Reliford, but refused to question the decision after the game.
"[Reliford] was right there," Bochy said. "It was hard to tell from where I was. I'm used to Barry's ball not hooking. He said he saw it clear."
"He called it," Bonds said calmly. "That's all that matters, dude. It's not my call."
First-base coach Willie Upshaw, the Giant with the best vantage point, confirmed Reliford's accuracy.
"I thought it was foul," Upshaw said. "I wouldn't argue with Charlie. I've seen it so many times here, playing first base. It's just a very tough call with that right field being so close."