ST. LOUIS -- Ian Stewart took a called third strike in his first at-bat then got an earful from Colorado Rockies manager Jim Tracy, who wants him to be aggressive when he sees a pitch to hit.

"If I have an at-bat like that he kind of jumps me: 'Come on, swing the bat. It's a weapon, use it. What are you doing?"' Stewart said. "I kind of like that. He'll pull me aside and get on me a little bit."

Stewart followed orders after that, homering twice and matching his career high with five RBI while Aaron Cook beat the St. Louis Cardinals for the first time in a 10-1 victory on Saturday night.

Stewart has four homers and 12 RBI the last five games, including all three of Colorado's three-run homers this season in the last four games. He hit a three-run shot to right on a full-count pitch in the fourth and a two-run shot to left-center on a 2-0 offering in the sixth, both off Todd Wellemeyer (5-6).

A 10-for-17 surge with four straight multihit games has raised Stewart's average to .231, and he leads the Rockies with 11 homers. Two of his three multihomer games have come this season, the other against the Astros at home on May 12, and 14 of his last 20 hits have been for extra bases. He also doubled Saturday night.

Tracy said Todd Helton will a day off Sunday but not the 24-year-old Stewart. Not the way he's going.

"When you're swinging the bat like that, shame on me if I don't write a lineup from day to day and he's not in there somewhere," Tracy said.

Cook (4-3) allowed a run and four hits in eight dominant innings, facing no batters with runners in scoring position. He lowered his career ERA against St. Louis to a still hefty 5.61, with the only damage coming on Rick Ankiel's third homer in the sixth. Cook had been 0-4 against St. Louis.

"I did not realize that, but I'll take it," Cook said. "We're starting to play better."

Clint Barmes added a three-run homer in the ninth off Blake Hawksworth, making his major league debut. The Rockies are 5-4 under Tracy after going 18-28 under Clint Hurdle.

The Rockies reached double digits in runs in three straight road games for the first time since April 7-9, 2006, at San Diego, totaling 31 runs after a four-game skid in which they had nine. They've beaten the Cardinals four straight times.

"It starts on the mound, and I don't know that you could have asked for a better performance than Aaron Cook gave us," Tracy said. "A heavy sinker, bowling ball-type sinker. Not a lot of chance to get the ball airborne unless he gets it up."

The Cardinals have lost six of nine, scoring three or fewer runs six times during that span.

"We've got to do better," manager Tony La Russa said. "We can do better."

Wellemeyer made it through seven innings despite his troubles with the longball, allowing only four other hits with six strikeouts. All three of his walks produced runs for Colorado.

"Sometimes you can get away with it," Wellemeyer said. "But not today."

Wellemeyer lost for the first time in four career decisions against the Rockies, and fell to 2-5 with a 5.72 ERA at home this season. He's 3-1 with a 4.56 ERA on the road.

Helton's sacrifice fly gave the Rockies the lead in the first. Wellemeyer walked Helton and Garrett Atkins with one out in the fourth and Stewart's 10th homer with two outs gave Cook a 4-0 cushion.

Notes

• Rockies SS Troy Tulowitzki (left hand contusion) entered as a defensive replacement in the seventh after missing his fifth straight start. Tracy said he'd start Sunday.
• Rockies CF Dexter Fowler was not in the lineup after fouling a ball off his calf, with Seth Smith replacing him in the leadoff spot.
• Cardinals slugger Ryan Ludwick (hamstring) is 3-for-31 with a homer and one RBI since coming off the DL on May 29 without a rehab assignment.
• All but two of the Cardinals' last 16 homers have come with the bases empty.