CHICAGO -- Josh Reddick spent some time during batting practice Friday needling A's teammate Josh Donaldson.

"I told him he wasn't strong enough to go the other way," Reddick said.

Reddick has seldom been happier to have been proved wrong. Donaldson delivered a monstrous and timely opposite-field home run with the bases loaded in the sixth inning, giving the A's all the runs they would get off Chicago White Sox ace lefty Chris Sale in a 4-3 win.

That victory, coupled with Texas' 6-1 loss in Toronto, moved the A's into first place in the American League West by one-half game.

"JD has put us on his back," Reddick said, looking at Donaldson's team-best .329 average and 41 RBIs. "At some points he's carried us."

Oakland Athletics’ Josh Donaldson (20) and right fielder Josh Reddick celebrate a 4-3 win over the Chicago White Sox after a baseball game June 7,
Oakland Athletics' Josh Donaldson (20) and right fielder Josh Reddick celebrate a 4-3 win over the Chicago White Sox after a baseball game June 7, 2013, in Chicago. (Charles Rex Arbogast/AP)

The A's have won 18 of their last 21 games, including beating Sale twice. This is a left-hander who won 17 games last year and had a 28-inning scoreless streak before Donaldson's sacrifice fly against him Sunday in Oakland carried the A's to a 2-0 win.

In his last 361/3 innings against all comers, Sale has allowed five runs. Donaldson has driven in all five.

"He's one of the best left-handers in the league, if not the best," Donaldson said. He picked on a 1-1 fastball up and away and hit it the other way, just as Reddick suggested he couldn't. "I wasn't trying to do too much.

"I'd already had two at-bats against him and was feeling very comfortable. He had to come in to me at that time, and I feel that any time a guy has to come at me, I'm going to be aggressive."

Being aggressive is second nature for Donaldson. He's now 10 for 18 in his career when batting with the bases loaded. He wasn't necessarily supposed to be the A's cleanup hitter against lefty pitching, but it's going to be difficult to get him out of that role. He's carrying a .350 average against left-handed pitchers, and five of his nine homers have come off lefties.

"That was big-time stuff right there," manager Bob Melvin said. "He's got a consistent approach and he understands what he has to do."

Before the Donaldson slam, the first of the year for the A's, the White Sox were able to gingerly build a 3-0 lead. The first of three hits for Tyler Flowers, a homer, was the first hit off Jarrod Parker in the third inning.

An inning later the White Sox scored an unearned run on Dayan Viciedo's sacrifice fly, and in the fifth Alejandro De Aza made it 3-0 with a sacrifice fly that followed hits by Gordon Beckham and Flowers. Parker was a little unlucky to give up three runs, but he held it there.

"He threw an 0-2 hanger (changeup) to Flowers, and we didn't make a play, and there was a bloop hit," Melvin said. "So it wasn't like he was getting knocked around."

And after the Donaldson slam, Parker put up scoreless innings in the sixth and seventh.

"They are an aggressive team, and I was able to keep the ball down," Parker said. "(After the grand slam) I was able to extend the game."

With Parker's seven innings of five-hit ball, the A's 18-3 run has seen Oakland starters throw at least seven innings 13 times, which as much as anything has been key to the club's success.

But defense helps, too, and closer Grant Balfour got a whole bucketful of defense from right fielder Reddick. Conor Gillaspie made a strong run at a game-tying homer, but Reddick, playing deep to cut off the possibility of a ball getting over his head, got back to the fence and jumped to bring back the homer.

  • The A's took first baseman Ryon Healy from the University of Oregon with their first Friday pick in the second day of the Major League player draft. However, the A's would take just one more position player, as seven of the nine picks the A's made were pitchers.

  • With two hits Friday, Reddick has six hits in his last 16 at-bats and his average is slowly climbing north. It sits at .190.

  • Donaldson came into the game with a .367 average, 15 doubles and six homers in his last 43 games. Donaldson had 37 RBIs in his career coming into the season and another 37 this year before his slam pushed him to 41 for the first 63 games of the season.

    Saturday's game

    A's (Tommy Milone 6-5) at Chicago (John Danks 0-2), 1:10 p.m., CSNCA