On Friday night, after the Cardinals had lost for a fifth time in six games, ace Adam Wainwright read a factoid about the opponent he’d face the next day. The Oakland Athletics swept five of their past six home series and had an early start on doing the same against the Cardinals this weekend.

Wainwright fired a text message to catcher Yadier Molina.

It recited the stat and concluded, “Let’s not let that happen.”

True to his ace title and stopper intentions, Wainwright didn’t. Backed by two home runs from rookie Matt Adams, Wainwright threw an unyielding five-hit complete game against the A’s and carried the Cardinals to a 7-1 victory at O.co Coliseum. Wainwright did not allow a run until the eighth inning, but left no doubt the game was his to finish for a league-leading fourth complete game of the summer.

“A ‘stopper’ is a guy who gets you out of a bad run when you really need a lift,” manager Mike Matheny said. “This is not that bad of a run, but still we needed it. The ace is the guy who has the leadership on the field and off the field. He fills all of those roles, and does it as well as anybody around.”

The win put the Cardinals in position to win their first interleague series during this 11-game stretch against American League teams. The A’s lost for only the third time in their past 18 home games. The Cardinals’ first humbling stretch of the season dropped them out of first place in the National League Central on Friday night and left them winless against AL clubs with winning records until Saturday.

A pitchers’ duel brewed early as Wainwright and A’s starter Jarrod Packer exchanged swift, scoreless innings through four innings. Each pitcher had nine outs from the first 10 batters he faced. While Wainwright quickly established his curveball, the righty Parker was working with what manager Bob Melvin called “as good as stuff as he’s had all year.” His leg gave out before his pitches did.

The first-pitch temperature Saturday was 84 degrees, the highest for any Oakland home game this year. Downright arctic compared to the blowtorch temps Cardinals pitchers face at home, and the heat caught Parker. In the fourth inning, he delivered a pitch and crumpled to the ground as Allen Craig tagged it for a double. Parker gripped his right hamstring and left the game with a cramp after several attempts to pitch through it.

“We might have been here a while had that not happened,” Melvin said.

Thrust into a long relief role like the Cardinals’ Joe Kelly had Friday night, Oakland righty Jesse Chavez stranded Craig in the fourth inning but sabotaged himself in the fifth. Adams opened the inning with a walk, and Chavez hit David Freese to jumpstart the Cardinals’ rally. A sacrifice bunt from Jon Jay and a sacrifice fly from Daniel Descalso put the Cardinals ahead 1-0. Matt Carpenter added an RBI single. In the sixth inning, Carlos Beltran’s leadoff double and a single from Craig chased Chavez (1-2) from the game. Melvin went to lefty Jerry Blevins with Adams looming on deck. The rookie slugger had 10 strikeouts in his previous 32 at-bats against lefties in the majors. He jumped the first pitch he saw from Blevins for a three-run home run.

Adams added a solo homer in the eighth for his first big-league multi-homer game. Both homers had the high, majestic loft, giving him six homers in 97 at-bats.

“He is a specimen,” Wainwright said.

Wainwright’s 15th career complete game came less than a week after the ace had expressed frustration with an early removal from his last start. At home against Texas, Wainwright was relieved in seventh inning and put in the unusual position of losing a game while watching from the bench. He said he disagreed with Matheny’s view that he was “laboring.” Wainwright later apologized, publicly and privately, to his manager for the comments.