Entrusted with the 6-5 lead that the Red Sox had built against Ubaldo Jimenez, the best pitcher in baseball thus far this season, Papelbon blew the save on just the second pitch he threw. Ian Stewart led off the inning by unloading on a 1-0, 96-mph fastball for an equalizing homer to right-center.
"Just fell behind and had to throw another flat fastball across the zone," said Papelbon.
More problems were ahead. Clint Barmes blooped Papelbon's 0-1 slider into center for a hit. With one out, Giambi hopped off the bench hit Papelbon's 1-0 splitter -- a rocket that soared through the thin air, ending the contest.
"He's an incredible closer," Giambi said. "To get a mistake that you're not going to get very often, I was just lucky enough to put the bat head on the ball."
Papelbon was highly displeased with the pitch that ended it.
"Just threw a flat, hanging split and usually that pitch gets deposited like it did," said Papelbon.
Why did this one seem to sting Papelbon more than some of the others he's had over the years?
"Just for the simple fact that I've been throwing the ball well and tonight I go out there and throw flat pitches," said Papelbon.
The Red Sox, who trailed 4-0 and 5-2 early, responded in a big way by tagging Jimenez for four runs in the top of the sixth to take the lead. The big hits came from Daniel Nava (RBI double), Darnell McDonald (two-run homer) and Marco Scutaro (bloop, RBI single). Even John Lackey got into the act, setting up Scutaro with a double to center, his second hit of the night. Lackey had come in to the game a 1-for-31 hitter lifetime.
"Don't count on that," said Lackey. "I was pretty fortunate. He's a special pitcher. For our guys to swing the bats like they did and give us a chance to win, you've got to give our offense a lot of credit. They've really been playing well for an extended period of time."
If the Red Sox had held on, it would have been one of their most satisfying victories of the season.
"With Nava, McDonald, shoot, even Lackey, we did some real good things," said Red Sox manager Terry Francona. "The outcome of the game was obviously not what we were looking for. There was so much good that happened -- we've just got to keep playing like that. Tough loss, but I love a lot of the things that we did."
Lackey had also rebounded from a shaky start and was in position to earn the win, setting down 10 of the last 11 batters he faced. The righty gave up 10 hits and five runs over 6 2/3 innings, walking none and striking out seven.
"I honestly felt probably about as good as I have all year," Lackey said. "It was obviously a pretty tough place to pitch and you've got to give those guys credit. I feel like they hit some pretty good pitches tonight. He ended up settling in and I kind of got into a groove at the end, that was nice."
As for Jimenez, who came in 13-1 with a 1.15 ERA, he gave up six runs and 10 hits over 5 2/3 innings.
"I know he's sick, but that stuff he was featuring early was as good as you're ever going to see," said Francona.
The Red Sox will try to stave off a sweep Thursday night when Daisuke Matsuzaka returns from the disabled list.
Against a pitcher of Jimenez's caliber, the last thing the Red Sox wanted to do was play from behind. But they were left with no choice, when Miguel Olivo ripped a two-run homer to left against Lackey in the second.
The Rockies added on in the third, loading the bases with nobody out, then scoring on a fielder's choice grounder by Brad Hawpe and a sacrifice fly to left by Seth Smith. The Red Sox were in a 4-0 hole against the pitcher with the best numbers in baseball.
But that didn't daunt the Boston batters. Nava came up with a two-out, two-run double to right-center in the fourth, cutting the deficit in half. Momentum sputtered briefly when Lackey gave up an RBI single to Jimenez, of all people, in the bottom of the fourth. Josh Reddick made a strong throw to the plate, but Barmes scored from second, running over Victor Martinez in the process.
Then, the Sox struck in a big way in the sixth, led by the homecoming hero -- McDonald.
"It definitely feels good to be able to do something like that, especially coming home," McDonald said. "Thirteen years in the Minor Leagues, to be able to come home and hit a home run like that, it feels great."
Though the Red Sox couldn't add on, they felt safe. They usually are when Papelbon is on the mound.
"There's nobody else I'd rather be out there closing down a game," said Lackey.