And for Cook, who entered the day with a minuscule 0.54 ERA, it represented just the second time in 31 outings this year he had given up a run.
"Cookie's not going to go the whole year and not blow a save," manager Bob Melvin said. "It's too bad it happened tonight, certainly. He's been so good for us that you just expect him to lock it down every single time."
"Tonight was one of those nights I didn't have anything," Cook said. "I did my best to battle. You saw the results."
The hard-throwing righty looked out of sorts from the start, throwing eight of his first nine pitches for balls en route to walking Buster Posey and Pablo Sandoval. Brandon Belt made Cook pay for his ineffectiveness, driving a ball past a diving Collin Cowgill in left field for a two-run double that tied the game.
"I knew he was being a little bit erratic, so if there was a strike, I was going to pounce on it," Belt said.
Cowgill rolled his left ankle on the play, and defensive replacement Jonny Gomes eventually took over for the youngster, whose condition was not known after the game. Melvin insisted "you can't fault him" for attempting the dive, and Cook agreed.
"He thinks he's going to make the catch," Melvin said. "It's certainly a different game if he makes the catch, and at some point in time when you're going after it, you make a decision. If he backs up, now we're not in the greatest situation in the world either, so I don't have a problem with him trying to make that catch."
Cook then offered up a base hit to Justin Christian before being pulled in favor of Sean Doolittle, who allowed two inherited runs to score to put San Francisco ahead for the first time all night.
"I just didn't have anything," Cook said. "That's been my hex all year, putting guys on. It came back to bite me tonight. Everything's a little bit out of sorts. What can you do? Come back and get them tomorrow."
"You feel bad, just because he's been doing it all season and he takes it hard, but he'll move on and forget about it," catcher Kurt Suzuki said. "He's not going to have a 0.20 ERA all year. Things are going to happen and you're going to run into some bad luck, in times where you just don't feel right. But he's strong mentally and the type of guy who says, 'Let's get 'em next time.'"
The rally couldn't be matched by the A's, despite Josh Reddick's ninth-inning solo homer, as Oakland collected just two hits after a three-run first inning against Lincecum.
The right-hander's past dominance over the A's, evidenced by a 5-2 record and 1.92 ERA entering Friday, has been well-documented. So, too, have been the struggles -- he's riding a career-high seven-game losing streak -- which have plagued the Cy Young winner in an inexplicably off year.
Oakland's hitters knew all about them and took advantage of those familiar woes, forcing the hurler to throw 43 pitches in the first inning. All three runs were plated before Lincecum even garnered a single out, at which point he was already staring down 32 pitches.
Suddenly, though, Lincecum entered cruise-control mode, not wanting to make it 11 games in which he's allowed four or more runs this season.
So he fanned Brandon Moss and then Suzuki, ultimately striking out the side by getting Cliff Pennington on strikes, too, to leave the bases loaded. He then managed to retire 15 of his next 17 batters, walking two but not allowing a hit while throwing 61 pitches over his final five innings.
"That's the Lincecum everybody has come to know," Suzuki said.
At the time, it appeared the tardy effort couldn't outdo the one showcased by Parker, as the young righty introduced the Giants to a different pitcher than the one that allowed them six runs in just two-plus innings while dealing with a knot in his neck and a touch of the flu back in May.
This time around, a healthy Parker limited San Francisco to one run on four hits with four strikeouts and two walks through six-plus innings.
Jerry Blevins and Grant Balfour combined for two perfect frames, before Cook unraveled in the final one.
"He's been great all year," Parker said. "Tonight is what it is. It's nothing that we're going to dwell on. [The bullpen has] been nails all year, and I don't think it's [anything] really to worry about."