OAKLAND, Calif. — The Yankees were comically bad on the bases and almost as inept with runners in scoring position.

Yet they took the opener of their four-game series against the A’s, 4-1, on Thursday night for two reasons: combined excellence from the heat-seeking trio at the back end of their bullpen and a dominating performance by Ivan Nova, who clearly is not interested in leaving the rotation anytime soon.

The Yankees (18-22), winners of nine of their last 14, had 10 hits but went 1-for-9 with runners in scoring position, including 0-for-7 through five innings against Kendall Graveman, who came in 1-5 with a 5.84 ERA and had lost four straight decisions.

Nova, making his third start in place of the injured CC Sabathia, allowed one run and four hits in six innings. He had thrown only 62 pitches when Joe Girardi made the call for Dellin Betances. In Wednesday night’s 4-2 victory over Arizona, Nathan Eovaldi had retired 18 straight and thrown only 85 pitches when Girardi pulled the plug.

“I had Dellin, I had the big three again,” Girardi said of Betances, Andrew Miller and Aroldis Chapman. They combined to throw three scoreless innings, with Chapman topping it off with his fifth save in five chances. “You look where I took him out in the lineup, they had four hits and those guys had the four hits, the next four hitters . . . We haven’t burned them out. I’m going to use them when I feel the time is right.”

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The Yankees’ nadir on offense came, oddly, in the inning in which they took the lead for good, the sixth. They collected four hits, including a double, in the inning but scored only one run.

Chase Headley led off the frame with a single but was picked off. Didi Gregorius was thrown out later in the inning trying to stretch a single into a double. But Aaron Hicks’ two-out RBI double, which made it 2-1, bailed out his teammates.

Carlos Beltran committed the most egregious mistake on the bases in the third when he lost track of the number of outs, failed to score from second with two outs on a dropped fly ball to right and was stranded. But he had a two-out RBI double in the inning and a two-out, two-run homer in the ninth to make it 4-1.

“It’s fortunate it didn’t hurt us,” Girardi said of the basepath blunders. “You’re not happy about it, but it does happen.”

Beltran offered no excuses.

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“A terrible mistake,” he said. “When I hit the double, I lost perspective of how many outs there were. Thank God today we were able to win, but situations like that could be bad because that could be the difference between winning and losing a game.”

With the 2-1 lead provided by Hicks, Nova set down the A’s (19-23), who had won four straight, in order in the bottom of the sixth, and the power arms took it from there.

As was the case Wednesday night, there was some drama. Betances, who had walked the first two Diamondbacks batters he faced before getting out of it, allowed a leadoff single by Josh Reddick, whose solo homer in the fourth had tied it at 1. Reddick stole second, but Betances struck out Danny Valencia and Khris Davis and got Stephen Vogt to foul out to third.

Miller struck out one in a perfect eighth and Chapman, now with a 4-1 lead after Beltran’s blast, struck out two in the ninth.

“I felt really good. I thought I was going to keep going,” said Nova, 2-0 with a 1.68 ERA in three starts. “He took me out, but I understand with the guys we have in [the back end].”