BOSTON -- The Boston Red Sox shelled struggling Oakland ace Sonny Gray for six runs in the fourth inning, and Jackie Bradley Jr. hit a grand slam and drove in six runs in a 14-7 rout of the Athletics in the opener of a three-game series Monday night.

David Ortiz stroked two doubles and Bradley had a two-run single in the big inning that wiped out a 4-1 deficit and helped send the A's to their third straight loss. Oakland has allowed 24 total runs in the past two games.

The Red Sox moved into a virtual tie for first place in the AL East with the Baltimore Orioles, whose scheduled game was rained out at Minnesota.

Brock Holt added a two-run homer in the fifth and the sizzling Bradley drilled his slam in the sixth.

Travis Shaw had three hits, and Ortiz drove in his second run of the game with his third hit -- a seventh-inning pop fly that dropped in front of home plate.

Boston starter Clay Buchholz (2-3) staggered through five innings to win his second straight. He allowed four runs on six hits and two walks with two strikeouts.

Bradley, who has a 15-game hitting streak, had three hits and is 21-for-55 (.382) during the streak. He is 6-for-8 with 15 RBIs with the bases loaded the last two seasons. The smooth-fielding Bradley did drop a fly ball for a run in the seventh inning -- his first error of the season.

Buchholz heard boos when Khris Davis homered to give Oakland a 4-1 lead in the third, but the right-hander made it through five before the bullpen took over.

Gray, who entered the game with a career-worst 4.84 ERA, including 7.88 in his last three starts, couldn't hold a three-run lead and was gone after 3 2/3 innings.

In his last three starts, Gray (3-4) has totaled 12 2/3 innings and yielded 18 earned runs on 21 hits. His season ERA ballooned to 6.00, and he has matched his career high of seven runs allowed each of his last two starts.

Yonder Alonso hit two doubles, and Coco Crisp had two hits, two walks and three runs for the A's.

Oakland's Josh Reddick saw his streak of eight consecutive hits end with a first-inning RBI groundout. The eight hits in as many at-bats (he also had a walk mixed in) tied a club record, last tied by Dave Magadan in 1997. Reddick, 10-for-12 over the weekend in Baltimore, went 1-for-4, driving in a run with a ninth-inning single.

Davis also had an RBI single in the ninth.

Oakland third baseman Danny Valencia left the game in the second inning with left hamstring tightness -- just three days after coming off the disabled list following his recovery from a left hamstring injury. He was injured opening the top of the inning with a single that was knocked down by second baseman Dustin Pedroia, and he wound up scoring his team's third run before leaving.

NOTES: Oakland manager Bob Melvin will name his starter for Wednesday's series finale on Tuesday, with RH Eric Surkamp the likely choice. Surkamp was 0-2 with a 5.59 ERA in four starts before being sent to the minors. ... Boston 3B Pablo Sandoval spoke for the first time since undergoing season-ending left shoulder surgery last week, saying, "People said that I was faking. You (the media) said that I was faking. I don't fake at all, because I (have proven) that I can play through pain. So, I don't have to prove it at all. I just now focus to do all my things out there. I got the surgery already, so now I'm going to focus on the rehab and get healthy (for) next year." ... Red Sox manager John Farrell was fined but not suspended for coming back onto the field after his ejection on Friday night. ... Oakland RF Josh Reddick became only the third A's player with 10 hits in a series went he went 10-for-12 in Baltimore. Sal Bando and Tony Phillips are the others.