"I said, 'I don't think they can get three through the infield right here," said a smiling Cook, who forced Ryan Sweeney to ground to Tulowitzki, who started the double play that ended the threat.
This kind of assuredness has led to the Rockies' winning 20 of their last 23 games, including three straight over the Athletics and four of six on the current nine-game road trip. The Rockies, who have tied a franchise record with 20 victories in one month, might find their confidence useful the next three games.
The Rockies, who trail the Giants by a half-game in the National League Wild Card standings, meet the NL West-leading Dodgers in a three-game set on the road.
The Dodgers are 8-1 against the Rockies and are 7 1/2 games ahead of them this year, but all that happened before the current success and the confidence that comes with it. Many of the wins have come against contending teams, and in both leagues.
"There was a question posed to me this morning -- do I feel like this upcoming series is a measuring stick?" Rockies manager Jim Tracy said. "As far as I'm concerned, it's three important games on the schedule."
The Rockies believe Cook (8-3) will measure up, always.
On Sunday, he went eight-plus innings, allowing one run but pitching out of two more situations of runners in scoring position and fewer than two out (in the second and fifth innings), and gave up nine hits. Cook is 5-0 with a 1.75 ERA in his last five starts.
"When Cookie's on the mound, it's pretty close to 100 percent that he's going to have a quality start and give us a chance to win," Tulowitzki said.
The game became tight in the ninth when the Athletics scored their only run. Closer Huston Street, who is beginning to give the Rockies the same confidence they have when Cook is on the mound, gave up two hits, including a Sweeney RBI single. But Sreet struck out Nomar Garciaparra and Mark Ellis, and forced a routine Adam Kennedy grounder, to pick up his 19th save.
Street, part of the trade that sent slugger Matt Holliday to the Athletics this winter, noted that his former club has lost 13 of 18 and five straight. He was happy the Rockies, who lost two of three to the Angels before arriving, took advantage.
"The way we're playing right now and the way they've been playing, this was a big series for us to bounce back," Street said.
Early this season, not even stalwart pitching could have won Sunday's game. The Rockies scratched out three runs by putting together some good at-bats in the second and sixth innings, but in all they struck out 13 times and left 10 on base.
But with the team confident overall, Cook's pitching was more than enough Sunday.
It was a different type of domination for Cook. Usually a ground-ball pitcher, Cook benefited from 10 fly outs to nine grounders. Some of that was a function of the swings of A's hitters such as Kennedy and Jason Giambi. Cook beat them with a four-seam fastball.
"I don't worry about the hits I give up," Cook said. "It's the runs I'm concerned about."
Chris Iannetta drove in the Rockies' first run with a second-inning fielder's choice, and Seth Smith doubled in another run for a 2-0 lead against Vin Mazzaro (2-3), who gave up three runs and five hits to take the loss but fanned eight in five innings. Carlos Gonzalez doubled in a sixth-inning run for a 3-0 advantage.
It was a smashing day and series for Gonzalez, who also was part of the Holliday deal.
Gonzalez went 2-for-2 with two walks after having a single and a triple in Saturday night's 11-9 victory. On Saturday, he threw out Holliday at the plate. On Sunday, he helped Cook by fielding Giambi's smash off the left-field wall -- which he became accustomed to last season -- with two out in the eighth and throwing him out at second.
Gonzalez lifted his average 48 points, to .228, in two games against his old club.
"I feel much better right now," Gonzalez said. "My swing is the same. Nothing has been changed. I'm just a little more comfortable at the plate, more confident."