He needed just one start to convince the Colorado Rockies of his ability.
Thompson's six strikeouts in 6 2/3 innings were three more than his previous best and he also earned his first career RBI in a 3-0 victory Thursday.
"This is the best I've seen him," Rockies manager Clint Hurdle said. "We probably took more funny swings today than we've taken off a right-hander in a long time."
The Cardinals took two of three from the defending NL champions, who totaled five runs in the series and managed just one in 16 2/3 innings against St. Louis starters. Colorado was 3-for-25 with runners in scoring position, two of the hits coming in the finale, but wasted one of them when Todd Helton was thrown out at the plate in the sixth.
"It's a good way to start the season, as good a club as that club is," Cardinals manager Tony La Russa said. "Very impressive."
Left-hander Mark Redman is scheduled to start when the Rockies play their home opener Friday, hoping to recapture momentum from a 21-1 run that propelled them into the World Series last fall. Redman said the sluggish first series makes him even more anxious to get back to Colorado.
"It seems like forever that we've been in St. Louis," he said. "It's a long time away from Coors Field and we'll be excited to get back in our own surroundings and with our own fans."
Thompson (1-0), a sinkerball specialist and swingman who's in the rotation while the Cardinals await several injured starters, walked two and allowed six hits. His only real trouble came in the sixth when Helton singled with two outs, Matt Holliday walked and Garrett Atkins singled, but Helton appeared tentative rounding third and was out in a close call after left fielder Skip Schumaker's strong throw to backup catcher Jason LaRue.
"Unbelievable play," said Thompson, who was backing up LaRue. "I was pumped up."
Thompson retired 10 batters in a row between the second and fifth, making the Rockies put the ball on the ground when they weren't striking out. Thompson, who totaled five strikeouts in 12 innings his last two starts last season, had no explanation for the career-best strikeout total.
"It's something that happens when you keep the ball down and make your pitches," he said. "That won't happen every time."
Rockies starter Ubaldo Jimenez (0-1) was in trouble throughout a five-inning stint, allowing three runs and seven hits. He walked five, struck out four and threw two wild pitches. Four of the innings he retired the first two batters.
"I know I can do better than this," Jimenez said. "I have to go after the hitters."
Rick Ankiel and Troy Glaus had RBI singles in the third as the Cardinals opened the inning with four straight base hits. Thompson, a career .176 hitter with 16 strikeouts in 34 at-bats after fanning his first two trips, singled in a run in the fifth after Jimenez issued two-out walks to Ryan Ludwick and LaRue.
Albert Pujols wrapped up a 5-for-10, three-walk series with two hits for the Cardinals, whose string of 165 consecutive regular-season sellouts ended with an announced attendance of 39,915 on Wednesday night. The crowd was listed at 33,748 for the series finale at new Busch Stadium, which opened in 2006.
Holliday was 1-for-10 in the season-opening series for the Rockies. Before this week he had been a .483 hitter (14-for-29) in two-plus seasons at Busch with five homers and seven RBIs.
"They pitched me tough the first couple of days and today I got myself out a couple times," Holliday said. "I just wasn't swinging very well."
Cardinals left fielder Chris Duncan missed his second start with a left hamstring strain and is day-to-day. ... Pujols reached safely in seven consecutive plate appearances, with three walks and four hits, before flying out to the warning track in the fourth. ... The five walks matched Jimenez's career worst. ... Colorado has won three of its last 12 games in St. Louis.