ST. LOUIS (AP) -- Mark McGwire's aching back was the only bad news for the St. Louis Cardinals on Opening Day.

McGwire, who missed the last two spring training games because of a lower back strain, was a late lineup scratch Monday. McGwire reinjured the back running before the Cardinals' 7-1 victory over the Chicago Cubs.

	Paquette, center, shouldn't get used to playing first base on a regular basis. Mark McGwire was scratched because of a lower back strain.

"He zig-zagged, and one of the zigs he felt a catch back there and he knew it," manager Tony La Russa said. "So we'll treat it and see how he is on Wednesday."

McGwire left Busch Stadium in the third inning and underwent an MRI at Barnes Hospital. The test showed no disc problems.

His replacement at first base, Craig Paquette, lined a three-run homer in the first inning, and his replacement in the cleanup slot, Fernando Tatis, also had an RBI single, a walk and two steals.

"That's kind of my job, to be ready whenever," said Paquette, who found out he was starting five minutes before game time. "Knowing he had a bad back, and that there was a chance with the cold weather I might get in there, I was prepared."

The other half of the latest McGwire-Sammy Sosa squareoff also was quiet in this opener of the Home Run Central, the division that also features Ken Griffey Jr. Cardinals starter Darryl Kile struck out Sosa twice and also got him on an infield popout. Slammin' Sammy, who's 2-for-11 thus far with no homers, also fanned in his final at-bat.

He wasn't blaming jet lag.

"I don't believe in that," Sosa said. "The guy pitched a great game and I've got to tip my hat to him. We haven't gotten it together yet, but we will."

Cubs starter Kevin Tapani, who gave up five runs in four innings, couldn't use the Tokyo trip as an excuse. The team left him behind on the two-game Japan split with the New York Mets so he'd be rested for his first start.

Tapani was one strike away from a scoreless first when Tatis's single drove in Fernando Vina, who led off the first with a triple off the center-field wall. After Jim Edmonds walked, Paquette lined the first pitch he saw -- a hanging slider -- over the left-field wall.

"That was pretty much the game right there," Tapani said. "They pretty much took control right there."

The Cardinals made it 5-0 in the fourth when Mike Matheny doubled and scored on a two-out single by Vina, who had three hits in his Cardinals debut.

Kile, 8-13 with a 6.61 ERA last year with the Colorado Rockies, allowed one run on two hits in six innings as he won his third straight opening start.

"I'd like to take some credit but I can't," catcher Mike Matheny said. "I called a spot, a pitch, and he hit it. He just executed every pitch."

Kile didn't allow a runner past first until the fifth when Shane Andrews got an infield hit, Damon Buford walked and Joe Girardi was hit by a pitch to set up a sacrifice fly by pinch-hitter Jeff Reed.

Heathcliff Slocumb, Mark Thompson and Dave Veres each pitched an inning in the combined three-hitter.

Shawon Dunston, who survived the final cut as the 25th man in a competition with Eduardo Perez on Sunday, made it 6-1 with a pinch-hit homer off Matt Karchner leading off the sixth. Eric Davis, still not 100 percent after rotator cuff surgery last August, homered off Andrew Lorraine in the seventh.

Game notes
Kile was 3-1 with a 2.42 ERA in spring training. ... Tapani hasn't won since June 24, 1999, a stretch of 11 starts. He was 1-0 with a 6.23 ERA in spring training. ... The Cardinals were 3-for-3 in the basestealing department, although the Cubs pitchers were more at fault than Girardi. ... The first name of McGwire's next target on the career homer list, Jimmie Foxx, is misspelled on the Cardinals' scoreboard as Jimmy. McGwire has 522 career homers and Foxx has 534 for ninth place ... The Cardinals' three-homer day tied a team record for opening day set in 1941. Enos Slaughter and Johnny Mize connected in that game. ... Before the game, the Cubs recalled infielder Julio Zuleta from Triple-A Iowa and optioned catcher Jose Molina to Iowa.