St. Louis has won 10 of 11 and is a National League-best 13-5, the best start for the Cardinals since they began 1982 with a 13-4 record and went on to win the World Series. The hot streak began with a three-game sweep at Milwaukee in the April 15 to 17 series, and St. Louis won the opener of this three-game series despite stranding 14 runners, leaving the bases loaded in the first, sixth and eighth.
Isringhausen, who had seven saves in seven chances, entered at the start of the ninth. He retired J.J. Hardy on a grounder and walked pinch-hitter Chris Magruder.
After throwing ball four to Magruder, his 10th pitch, Isringhausen bent over and winced from an abdominal strain in his right side. Manager Tony La Russa and trainer Barry Weinberg came out.
Randy Flores then picked up his second career save when Damien Miller grounded into a double play.
Jeff Suppan (2-2) raised his record against Milwaukee to 9-2, including both of his victories this year. He threw 97 pitches in five-plus innings but was hurt only by Hardy's two-run single in the second.
Pujols' sharp grounder took a bad hop and handcuffed third baseman Russell Branyan to drive in the game's first two runs in the first. He doubled again in the fourth to put the Cardinals ahead 4-2, making Doug Davis (2-3) pay for walks to Suppan and Larry Walker.
Pujols is 11-for-28 with two home runs during a seven-game hitting streak and leads the Cardinals with 15 RBIs.
He also improvised on a grounder to first that veered sharply, rolling while making a rainbow throw to Suppan covering at first to nip Branyan in the fourth.
Davis threw 94 pitches in four innings, walking five, and lost to the Cardinals for the second time in three starts. He gave up four runs on four hits with four strikeouts and has lost his last three decisions, allowing 12 earned runs in 13 2/3 innings.
Brewers first baseman Lyle Overbay required 12 stitches to close a cut on his jaw sustained when he landed awkwardly over the tarpaulin after making a catch in foul territory in the first. But he was still in uniform and on the bench later in the game.
Wes Obermueller, who would have started Monday's rained out game in place of ailing Ben Sheets, allowed an unearned run, one hit and three walks in 2 1/3 innings of relief for the Brewers. He escaped a bases-loaded jam in the sixth when Jim Edmonds grounded out on a 3-1 pitch for the last out.
Obermueller, a .385 hitter with five RBIs last year, doubled and scored on Geoff Jenkins' two-out double in the seventh to cut the deficit to 4-3.
St. Louis added a run in the seventh on So Taguchi's one-out walk, a wild pickoff throw by Obermueller and a two-out RBI single by Abraham Nunez.
* Pujols has reached base in 26 consecutive regular-season games. He's 6-for-13 against Davis with one homer and 7-for-15 against the Brewers.
* Yadier Molina is 0-for-14 against Milwaukee pitching. ... Walker was on base all five at-bats, going 2-for-2 with a hit by pitch and two walks.