Manager Aaron Boone #17 of the New York Yankees looks...

Manager Aaron Boone #17 of the New York Yankees looks on from the field prior to a game against the Detroit Tigers at Yankee Stadium on Friday, Aug. 31, 2018 in the Bronx borough of New York City. Credit: Jim McIsaac

OAKLAND, Calif. – Aaron Boone liked what he saw from the A’s, even in defeat.

“I remember them being tough in May, even though it wasn’t rolling yet,” Boone said Monday.  “I remember coming away really impressed with who they had.”

Before this week, the last time the Yankees had seen the A’s was May 11-13 at the Stadium and Oakland did not project much in the way of excellence.

The Yankees took two of three to improve to 28-12 at that point of the season while the A’s slid to a ho-hum 19-21. 

They gave no indication a “roll” like the one Boone spoke of was coming. 

But it was.

The A’s entered Tuesday night an MLB-best 49-20 since June 16 and 83-56 overall, on a collision course with the Yankees for the American League wild-card game. The Yankees brought a 3 ½ game lead over the A’s into Tuesday night for the top wild-card spot.

“They’ve got some premium players, no doubt about it,” Boone said. “And obviously they’ve had some guys really come of age and emerge as those impact kind of players, especially in the second half of the season. You have to make pitches against them.”

While the lineup is deep – nine A’s have at least 10 homers, with Khris Davis’ 40 leading the way – a bullpen loaded with power arms commands much of the attention with the club.

There is, for example, rookie righty Lou Trivino, who posted a 1.45 ERA over his first 45 appearances this season and, of course, All-Star closer Blake Treinen, who brought the lowest ERA among relievers (0.91) into Tuesday.

It is no surprise, the A’s entered Tuesday 59-0 when leading after seven innings, the only team in the Majors that had not lost when leading after seven. 

“Very similar to the bullpen we have, when we get a lead we feel really good about our chances and when they get a lead I’m sure they feel really good about their chances too,” Brett Gardner said. “They’re running a bunch of good arms out there at you.”

A’s starter Trevor Cahill went five innings Monday and Oakland manager Bob Melvin used Trivino, Yusmeiro Petit, Ryan Buchter and Jeurys Familia to get the ball to Treinen, who pitched a perfect ninth for his 36th save. The quintet did not allow a hit over four scoreless innings of work.

“They do a good job of shortening the game,” Boone said. “You know you have to play well to beat these guys.”

Though the A’s offense doesn’t the attention of that units like the Red Sox and Yankees’ do, it is impressive in its own right.  Coming into Tuesday Oakland ranked fifth in the majors in runs (667), third in homers (191) and slugging (.437) and second in doubles (282) and extra-base hits (491).

“They put good at-bats together,” said CC Sabathia, who allowed five runs (four earned) and seven hits over 3 1/3 innings Monday. “They foul off good pitches. It’s a good lineup. I have to make better pitches if I face them again.”

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