"It was obviously 110 degrees out there and getting ourselves down five runs in the first two innings is pretty tough," Pujols said, exaggerating on a day when the temperature was 90 for the first pitch. "But we've got a lot of outs left, and I think after the second inning Todd really found himself out there."
Wellemeyer (8-4) allowed one hit in his last 4 1/3 innings after surrendering five runs on four hits in the first two frames and Ryan Franklin worked the last two innings for his 14th save in 18 chances.
The Cardinals have won four in a row, also erasing a 3-run deficit in Friday's 11-7 victory, and matched their season best of 13 games above .500 for the third time. They are 5-1 against the Padres.
"I wish I could have taken back those first two innings, because I figured it out after that," Wellemeyer said. "You give up five runs, you're like 'Man, I hope I didn't lose this game this quick for everybody.'"
Randy Wolf (6-10) was knocked out in the sixth after a strong beginning for the Padres, who have lost five in a row and eight of 10. Rookie Edgar Gonzalez hit a three-run home run, matching his career best for RBIs.
Gonzalez, who hit .302 for the Cardinals' Triple-A affiliate in Memphis last year but never got a callup, is 6-for-12 against St. Louis with two homers, four RBIs and four runs the first three games of the series. The Padres' second baseman, 29, is the older brother of first baseman Adrian Gonzalez.
"It does feel pretty good to show them I can play at this level," Gonzalez said. "They probably didn't think I could do it."
Pujols is second in the National League with a .359 average, his best since he was at .364 on June 5, after going 3-for-4. His three-run double highlighted a four-run fifth that closed the gap to a run and his infield RBI single in the sixth off Cla Meredith, a sharp grounder into the hole that shortstop Khalil Greene stopped but could not corral, put the Cardinals ahead 6-5.
Adrian Gonzalez had an RBI double on a tailing, dipping drive that center fielder Rick Ankiel overran before slipping when he attempted to retrace his steps, and Kevin Kouzmanoff added a sacrifice fly to put the Padres ahead in the first. The Gonzalez play was ruled an error until the fourth, after official scorer Jeff Durbin had a chance to view numerous replays.
Cardinals manager Tony La Russa thought it should have been an error, reasoning that a major league outfielder should make the play. Ankiel disagreed and made a jet engine noise to help in describing the unusual movement, although he felt bad for Wellemeyer.
"If the ball cuts like that, it's really nobody's fault, know what I mean?" Ankiel said. "There's nothing I can do, you just hang with them."
Edgar Gonzalez' fifth homer, a three-run shot, made it 5-0 in the second. The Padres advanced one more runner into scoring position against Wellemeyer, then missed two chances against the St. Louis bullpen.
Ron Villone struck out Adrian Gonzalez and got Kouzmanoff on a flyout with the bases loaded in the seventh and San Diego had two men on and one out against Franklin in the eighth before pinch hitter Luis Rodriguez grounded into a double play.
Wolf, making his first appearance in St. Louis since Aug. 16, 1999 when he played for the Phillies, allowed three hits the first four innings before running into trouble in the Cardinals' four-run fifth. Pujols cleared the bases with a double and Ankiel dropped in an RBI single just in front of right fielder Brian Giles to cut the gap to one.
Wellemeyer singled to lead off the fifth, but Wolf said the biggest problem was walking leadoff hitter Skip Schumaker.
"That kind of snowballed there," Wolf said. "Then you leave a ball up to Pujols. You have to make a better pitch than that, obviously."
Wolf is 1-5 with a 6.63 ERA on the road and the Padres are 1-9 in his 10 road starts. A throwing error by third baseman Kouzmanoff on Brendan Ryan's routine grounder opened the door for a pair of unearned runs in the Cardinals' go-ahead sixth.
Cardinals RF Ryan Ludwick got an unusual assist in the first, throwing out Jody Gerut at second on what should have been a single by Edgar Gonzalez, when Gerut waited too long for the ball to drop in. ... Giles slammed into the wall after making the catch down the line on Troy Glaus' opposite field drive to end the sixth, but trotted off without assistance. ... Cardinals LHP Randy Flores walked Gerut in the seventh in his first appearance since coming off the DL on Friday, and has walked seven of his last 15 batters. ... Paid attendance of 45,399 was the Cardinals' 23rd sellout in 50 home dates. ... The Padres are 11-18 in one-run decisions, and 2-10 on the road.