OAKLAND -- Mark Trumbo hit his first grand slam of the year as part of a five-RBI day, and Chris Tillman won for the 15th time, as the Orioles held off a late A's surge and avoided a sweep at the Coliseum on Thursday with a 9-6 win.The A's brought

OAKLAND -- Mark Trumbo hit his first grand slam of the year as part of a five-RBI day, and Chris Tillman won for the 15th time, as the Orioles held off a late A's surge and avoided a sweep at the Coliseum on Thursday with a 9-6 win.

The A's brought the potential game-winning run to the plate in the bottom of the ninth. But Orioles closer Zach Britton got Danny Valencia to ground out to second base with the bases loaded for his 35th save, moving Baltimore within a half-game of first-place Toronto. Britton has not allowed an earned run in 39 straight appearances, an MLB record.

Baltimore's offense finally erupted after scoring only three runs through the first three games of the series. A three-run fourth, capped by a two-run double by Pedro Álvarez , snapped a scoreless streak of 17 consecutive innings dating back to Tuesday. The O's only added on from there, loading the bases an inning later for Trumbo, who hit his Major League-leading 32nd homer and third career grand slam to make it 7-0.

"[Trumbo's] had a good season," said Orioles manager Buck Showalter. "Just because he hasn't been perfect the last week or so, a lot of people would like to trade places with him statistically. We're lucky to have him, or we wouldn't be where we are."

• Trumbo slams door on slump

Tillman is now tied with Boston's Rick Porcello for the second-most wins in the American League, trailing only Toronto's J.A. Happ (16). Tillman allowed a two-run homer to Ryon Healy in the fifth, but was otherwise solid, holding Oakland to five hits over seven innings while striking out four. It was the seventh straight quality start by a Baltimore starter on the team's 10-game road trip.

Andrew Triggs , a converted reliever making his second start of the season, was charged with his first loss of the season. He was the A's eighth different starter in their last eight games, the first time that's occurred since 1961. Triggs ran into trouble in the fourth inning, as Baltimore sent seven batters to the plate in a four-hit, three-run frame.

Oakland's bullpen didn't fare much better, allowing six runs in five innings of relief, including Adam Jones ' 23rd home run of the season in the seventh inning. Baltimore led 9-2 until the A's narrowed the deficit in a four-run eighth inning, sparked by a Max Muncy homer and a two-run double by Yonder Alonso .

A's take series, show resolve vs. AL juggernaut

MOMENTS THAT MATTERED

Britton blanks another opponent: Britton allowed a one-out walk and back-to-back two-out singles in the ninth, but kept the A's off the board. His 39th straight appearance without allowing an earned run moved him past Brett Cecil and Craig Kimbrel for the longest streak in MLB history. The last time Britton yielded an earned run was on April 30, when he allowed one on one hit to the Chicago White Sox. He gave up three unearned runs on June 21 vs. the Padres.

A's pitching magic runs out: Baltimore struggled mightily through three games in this series, no matter who the A's started. Kendall Graveman was strong Monday; another reliever-turned-starter, Zach Neal , managed 5 1/3 innings Tuesday; and Ross Detwiler threw eight shutout innings Wednesday in his first Major League start in more than a year. Triggs opened with three scoreless innings, appearing to embark on yet another unlikely strong performance, before stumbling in the fourth.

"Today he was a starter out of necessity," A's manager Bob Melvin said of Triggs. "It's well-documented we've had a lot of pitchers hurt. ... I thought he pitched really well in the early innings."

Finding offense: The Orioles were hard-pressed for offense in their first three games in Oakland. But, putting the ball in play became contagious in the fourth and fifth innings, as Baltimore broke the game wide open with seven runs. Manny Machado and Chris Davis started the rally in the fourth with a pair of one-out singles. Trumbo then put the Orioles on the board with a single to score Machado, and Alvarez broke the inning open with a two-run double to center field. The Orioles hadn't scored in 17 innings before the three-run rally. Trumbo, who was batting .115 in his last 16 games entering Thursday, then followed up that inning with a two-out grand slam to give Tillman a seven-run cushion.

"The last couple days, we haven't been able to get anything going," Alvarez said. "To put some runs on the board obviously felt good. It's always good when we can give our pitchers some breathing room."

Healy helps his cause: Healy robbed Machado of a hit in the first inning, tumbling to his left to snare a grounder before popping up and throwing Machado out at first. Four innings later, Healy made an impact at the plate, belting a two-run homer to left. Healy, who hit .316 over the first five games of his career, was batting .191 in his last 15 games prior to Thursday.

"He's been a little bit ... I don't want to say struggling ... but you find out the character of a young player who comes up and starts out real good and goes through some hard times," Melvin said. "They're making some better pitches on him. We've seen and we know he's a fighter. To come back and make some good plays and swing the bat well ... usually your game kind of surfaces again."

QUOTABLE

"It's fun to be a part of, that friendly competition." -- Tillman, on a strong stretch from O's starting pitchers

AFTER FURTHER REVIEW

The A's challenged the second-to-last play of the game after Brett Eibner appeared to be thrown out at third base by Jonathan Schoop . Eibner had rounded third after Khris Davis singled up the middle, and replay showed he dove back to the bag in time, which led to the call on the field being overturned and the game continuing.

"You just can't make the last out over there, and he knows that," Melvin said. "He scrambled back and he was safe. Give him some credit ... There has to be some awareness there, and it was just enough to get him back to the bag."

WHAT'S NEXT

Orioles: The Orioles will open a three-game series against the National League West-leading San Francisco Giants at AT&T Park on Friday night at 7:15 p.m PT. Right-hander Dylan Bundy will be on the mound. He set a career high with nine strikeouts in his last start Sunday.

Athletics: The A's begin a three-game series with the Mariners on Friday at 7:05 p.m. PT, concluding a 10-game homestand. Sean Manaea (3-7, 4.58) starts for the A's, facing the Mariners for the second time this season. He allowed four runs in five innings against Seattle on May 4, earning a no-decision. Manaea is 1-3 with a 3.12 ERA over his last eight games.

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