OAKLAND, Calif. -- Jed Lowrie belted a lead-flipping home run in the fourth inning, Josh Donaldson added an insurance shot in the seventh and the Oakland bullpen shut down St. Louis Cardinals on one hit over the final three innings as the Athletics completed an interleague series win with a 7-5 victory Sunday afternoon.
In taking two of three from the Cardinals, the second-place A's remained a half-game behind American League West leader Texas while improving their interleague record this season to 9-3.
Lowrie's home run, his fifth, came an inning-and-a-half after he allowed Matt Holliday's routine grounder to roll through his legs for a run-producing error that extended St. Louis' lead to 5-2 in the third inning.
After the A's narrowed the gap to 5-4 with a two-run third of their own, Lowrie followed a double by Chris Young with a second-pitch blast over the 362-foot sign in right field off Cardinals starter Jake Westbrook (4-3).
Young had entered the game in the top of the inning after Oakland's starting center fielder Coco Crisp complained of back spasms and was given the rest of the day off.
Donaldson went the opposite way to nearly duplicate the trajectory of Lowrie's homer in the seventh, a two-out solo shot off Cardinals reliever Trevor Rosenthal that extended the A's lead to 7-5.
Left-hander Tommy Milone (7-7) snapped a two-game losing streak despite surrendering three Cardinals home runs, including two to the first four batters of the game.
Relievers Sean Doolittle, Ryan Cook and Grant Balfour protected Milone's lead over the final three innings, with Balfour recording his 19th save in 19 opportunities with a hitless ninth.
St. Louis appeared on its way to becoming the majors' third 50-win team when it built a pair of three-run leads in the first three innings.
Carlos Beltran's two-run homer, his 19th, and clean-up hitter Allen Craig's ninth went back-to-back in the top of the first inning, staking Westbrook to a 3-0 lead before he ever took the mound.
Matt Carpenter, who had doubled and scored in the first, led off the third with a solo shot, his seventh. The Cardinals' fifth run -- the second of the third inning -- scored on Lowrie's error.
Lowrie had an RBI single and Yoenis Cespedes a run-scoring double in a two-run Oakland first. Two Cardinals errors helped produce two A's runs in the third, a four-hit inning that featured a double by Brandon Moss.
Milone, who lost a sure win when he couldn't complete the mandatory five innings in his last start, almost suffered the game fate Sunday as well. After giving up three runs in the first inning and two in the third, he put runners on first and second with one out in both the fourth and fifth innings before escaping jams as the A's had relievers warming in the bullpen.
He left after six innings, having thrown 94 pitches. He gave up three home runs among seven hits and allowed five runs, four of which were earned. He walked two and struck out five.
Westbrook, who brought a 2.21 ERA into the game, endured his worst outing of the season. After having surrendered just 14 earned runs in his first nine starts, the veteran right-hander got torched for six runs on 10 hits in just four innings. He walked two and struck out three.
The A's out-hit the Cardinals, 12-8.
NOTES: The three home runs allowed by A's LHP Milone raised his season total to 19, which is tied with Kansas City's Jeremy Guthrie for the most in baseball. ... Oakland RHP Jerrod Parker, who had to be pulled in the fourth inning Saturday because of a right-hamstring injury, reported to the ballpark in some pain Sunday morning and the A's thus could not confirm he would be able to make his scheduled start Thursday against the Chicago Cubs. Parker is scheduled to throw a bullpen session Tuesday to determine his availability for Thursday. Minor-leaguers Dan Straily and Sonny Gray are possibilities if Parker cannot make the start. ... Cardinals 1B Matt Adams, who had his first career multihomer game in Saturday's 7-1 win, was a late scratch from starting Sunday because of what was called food poisoning. He was called upon to pinch hit with one out in the ninth and struck out against Balfour. ... Both teams are off Monday. ... The Cardinals complete a tour of the American League West when they open a three-game series in Anaheim against the Los Angeles Angels on Tuesday, with All-Star candidate RHP Lance Lynn looking for an 11th win. ... A's RHP A.J. Griffin goes after his second consecutive interleague shutout when he opens a three-game home series Tuesday against the Chicago Cubs.