But after missing most of last season after doctors found blood clots in his lungs in 2004, Cook did just that, winning a career-high and franchise-record sixth straight decision and leading the Rockies to a 4-2 victory over the NL West-leading San Diego Padres.
"Initially we just wanted him to be able to get healthy," Rockies manager Clint Hurdle said. "And now for him to come back and be able to pitch, that's a plus."
The Padres' second loss in three games to last-place Colorado dropped them back to .500 (76-76), but their lead over second-place San Francisco remained at five games in the NL West. The Giants lost 2-0 at Washington on Thursday.
San Diego, which has struggled to score runs as it tries to hold on to the lead in the weak West, lost 20-1 on Tuesday night and could muster only a series split of the four-game series in Denver.
"It's a tough loss," Padres manager Bruce Bochy said. "I thought Adam [Eaton] threw the ball well. We just couldn't quite cash in on a couple of opportunities there."
The Giants open a three-game series at Coors Field on Friday, followed by a four-game home series against the Padres starting Monday. San Diego opens a three-game series at Arizona on Friday.
It has been a long recovery for Cook since Aug. 7, 2004, when he left a game complaining of dizziness and shortness of breath. Doctors discovered the potentially life-threatening blood clots, forcing Cook out of baseball until July 30.
Since his return he's been the Rockies' best pitcher, allowing 14 earned runs in his last seven games.
For eight innings on Thursday, Cook seemed unstoppable. He allowed eight hits and retired the side in order in the first, third, fifth and eighth innings. He got 15 groundball outs and had to work out of a jam only twice.
"It was self-preservation right there," Cook said of the catch that left him with a bruised pinkie and a bandaged hand.
But in the ninth, he was forced to leave after allowing singles to Giles and Klesko. Greene then hit a two-run double to center off Brian Fuentes, who record his 30th save.
Helton's two-run homer to right off Eaton in the seventh gave the Rockies a 4-0 lead. Eaton (10-5) then was pulled after allowing four runs and seven hits over 6 1/3 innings.
"That was an impressive at-bat," Bochy said. "He fouled one off his knee and he battled, then he got one he could handle."
With the win, the Rockies guaranteed they would finish the season with less than 100 losses -- a much better record than many predicted for the inexperienced team.
Cook, too, is doing better than many expected. He said he was probably pitching better than ever before in his career, which he credited, at least partially, to his illness.
"It just makes you stronger, more mentally tough when you're on the mound, knowing I was at a near-death experience, and I'm just playing a game out there," he said.
The attendance of 18,119 was an all-time low in the 11-year history of Coors Field. The old record was 18,184, set May 12 against Arizona. ... Despite the loss, San Diego won the season series 11-7. ... Right fielder Brad Hawpe got his 10th assist this season in the second inning, when he threw out Hernandez at the plate. ... Center fielder
Dave Roberts and right fielder Giles collided in the third when they both went after a fly ball hit by Helton. ... Colorado's Matt Holliday had his 10-game hitting streak ended.