Wainwright (8-3) allowed eight hits and one run without walking a batter to close out the first doubleheader between the Giants and Cardinals in St. Louis since July 16, 1978. Wainwright threw 106 pitches and 73 strikes.
Wainwright also helped with his bat when the Cardinals broke through against San Francisco's Madison Bumgarner (4-4) with three runs in the third.
Pete Kozma started the inning with a walk, and he advanced to third when Wainwright followed with a double to left-center. Kozma scored on a fielder's choice to first by Jay, and one out later, Beltran drove Wainwright and Jay home with a single to center.
Bumgarner lasted six innings and allowed five runs on six hits with one walk and six strikeouts.
In the opener, Miller (6-3) scattered six hits, stranding seven runners. His ERA dropped to 1.82. Miller struck out seven with one walk.
Matt Cain (4-3) allowed seven runs in six innings, falling to 0-3 at Busch Stadium with an 8.87 ERA in four starts.
Cain struggled in the third, when he threw 40 pitches. In the other five innings he pitched, Cain set the Cardinals down in order. He threw 101 pitches, striking out nine with no walks.
The Cardinals had seven runs on nine hits - seven singles and two doubles - in the third when St. Louis sent 12 men to the plate.
Cruz, starting at catcher instead of Yadier Molina, smacked a two-run double. Descalso hit a double and a single while Kozma had two singles in the outburst.
NOTES: This was the first time the Giants and Cardinals played a doubleheader since April 9, 1994, when the teams met at Candlestick Park and split. ... David Freese extended his hitting streak to 11 games with an infield single in third in the nightcap. ... San Francisco has lost its last seven road games and nine of its last 10. . . . Cardinals rookie Keith Butler, who was called up Thursday from Triple-A Memphis, pitched a scoreless ninth in the opener in his debut . He is the 10th rookie to debut for St. Louis this season.
Link to box score: St. Louis 7, San Francisco 1 (Game 2)
Link to game discussion at The Cardinal Nation message board