"I just missed a slider before, fouled it straight back," Giambi said. "I was thinking, 'God, I'd love to have that one again. And he ended up making that same mistake."
The Rockies, who had been 0-55 this season when trailing after eight innings, were down to their last out when Dexter Fowler blooped a double to shallow center off Leo Nunez (1-3). The ball dropped among three Marlins but Fowler was nearly caught in a run down when infielder Alfredo Amezaga threw back into second. However, third baseman Greg Dobbs, covering second, was off line with his throw to first. Fowler, who had been retreating on the baseline, shifted gears and cruised into second base.
It was another close call, though, for the Rockies.
"For a second, I thought, 'Here we go again.' It was starting to play out again, that frustrating 'Rock show," Giambi said. "We just haven't been able to push through, so it was exciting to finally push through."
Carlos Gonzalez followed Fowler's double with one of his own to right field to tie the game.
Troy Tulowitzki was walked intentionally and Randy Choate relieved Nunez, who had entered with two outs in the eighth. Giambi followed with a drive into the seats in right field for his 11th home run, setting off a celebration at home plate after the Rockies' first ninth-inning comeback.
"I hung a pitch," Choate said of the slider he threw Giambi, who had been hitless in four previous at-bats against Choate. "I've had success against him in my career. I don't think I did anything different. It's part of playing here. I'm not going to blame it on the air. I just hung it out over the plate. I think he was sitting on the pitch. He just took a pitch that was up and hit it out."
Matt Belisle picked up the victory with 1 2/3 innings of scoreless relief.
The game was a milestone for Florida manager Jack McKeon, even if it was a memorable loss, as he managed his 2,000th major league game. McKeon returned for his second stint as manager of the Marlins -- he led the team to a World Series title in 2003 -- after Edwin Rodriguez resigned on June 19.
"It's nice. It shows you've been around a long time, that's all," McKeon said of his managing milestone before the game.
And afterward? "It was one of those nights," he said.
McKeon began his managing career in 1973 with the Kansas City Royals and has also managed the Oakland Athletics, San Diego Padres, and Cincinnati Reds. At 80, he's baseball's second-oldest manager behind Connie Mack (87) and has a career record of 1,035-965.
Florida's Clay Hensley struck out a season-high five in 5 2/3 innings. He allowed three runs, eight hits and walked none.
Kevin Millwood, making his second start since joining the Rockies earlier this month after spending much of the season with Boston's Triple-A affiliate, went six innings and allowed four runs and seven hits.
Tulowitzi put the Rockies in front 3-2 when he connected for his 24th homer, a two-run shot off Hensley in the third inning.
Marlins reliever Edward Mujica had to leave the game with one out in the eighth with a right lat strain. ... Millwood has allowed at least two runs in the first inning in 13 of his past 23 starts. ... The Rockies have hit home runs in eight straight games. ... Fowler leads the Rockies with 12 triples. ... The Rockies have selected the contract of LHP J.C. Romero and designated RHP Edgar Gonzales for assignment. ... Stanton, who drew a fifth-inning walk, has 21 since the All-Star break, tops in the NL during that span. ... Buck's 14 homers are the most by a Marlins catcher since Miguel Olivo hit 15 in 2007. ... Colorado third base coach Rich Dauer, who missed Sunday's game in St. Louis after suffering a broken nose when he was hit in the face by a throw during batting practice, was back on the field for the Rockies on Monday night. ... Florida's Anibal Sanchez (6-6) faces Colorado's Jhoulys Chacin (9-9) on Tuesday.