OAKLAND, Calif. — When Aroldis Chapman went on the disabled list with a left knee wracked with tendinitis on Aug. 23, the Yankees knew they were going to miss the All-Star closer with triple-digit fastballs and knee-buckling sliders.

Yet, if ever a team was equipped to handle such a loss it was the Yankees, who had Zach Britton, Dellin Betances and David Robertson all with closing experience. And there was Jonathan Holder and Chad Green to get the game from the starter to the late innings.

Britton and Robertson were former closers and successful ones. Betances had closer stuff but has worked in front of Chapman the past three seasons, filling in whenever Chapman has been injured.

Betances has been Aaron Boone’s choice to close games when he is available and Britton has been pedestrian in 16 appearances since arriving from Baltimore.

That leaves the 33-year-old Robertson, who has been sensational since Chapman went on the shelf. Never more so than he was in the seventh inning of Tuesday night’s 5-1 win over the A’s that boosted the Yankees’ AL wild-card lead to 4 ½ games in the chase for home field in the one-and-done tilt.

In five games since Chapman went down entering Wednesday night’s, Robertson had been sensational. He was 1-0 with two saves, hadn’t allowed an earned run in five innings, fanned 11 while walking just three and held hitters to a .111 batting average and a .516 OPS.

When J.A. Happ gave up a leadoff single to Matt Chapman in the seventh with the Yankees leading, 2-1, Aaron Boone called for Robertson. He fanned Jed Lowrie for the first out and thought he had Khris Davis struck out, but didn’t get the check-swing call. Robertson rebounded to strike out Stephen Piscotty with a 0-2 pitch and Matt Olson with a 2-2 offering to escape the jam.

“He was great, he mixed his fastball in but obviously when he needed the big pitch he mixed in fastballs and really had his breaking-ball command going,’’ Boone said. “He went through the heart of their order, obviously, in a big situation.’’

Working in and out of trouble has been Robertson’s calling card for much of his career. As Mariano Rivera’s setup man until 2013 it seemed Robertson was escaping jams nightly. When he saved 39 games the following year, the high-wire act continued. He went to the White Sox as a free agent and saved 84 games in two-plus years before being dealt back to the Yankees in late July of last year with third baseman Todd Frazier and right-handed reliever Tommy Kahnle.

“I don’t like being in those situations but when I get in them I have to find a way to get out of them. The team is counting on me to get out of them,’’ Robertson said. “It seems like I have been in that situation more than anybody else. I have had more opportunities than anyone else to get out of.’’

When Robertson arrived for a second tour in The Bronx, he said he would do whatever Joe Girardi and pitching coach Larry Rothschild wanted.

Nothing has changed with Boone at the helm.

“I try to make the best of every opportunity I get, whatever situation they put me into I try to make every pitch,’’ said Robertson, who hadn’t allowed an earned run in his past dozen outings and had struck out 18 in 12 ²/₃ innings while holding hitters to a .119 batting average and a .443 OPS.

Robertson can still find trouble and escape it, but he is attempting to lower his stress level in those situations.

“Those eighth-inning guys like me back in the day we used to put a lot of guys on base and same thing when in the ninth. I was probably a heart-attack closer when I was here in New York,’’ Robertson said. “Now I am trying to get out of that role and be a little more efficient. I dig deep and do my best to get out of those situations.’’