Reliever Sean Doolittle celebrates with catcher Matt Wieters after Doolittle closed out the Nationals’ 3-2 win Thursday night. Doolittle has converted all seven of his save chances since Washington acquired him from Oakland. (Greg Fiume/Getty Images)

Sean Doolittle heard the chants between pitches and batters Thursday night at Nationals Park as he navigated the ninth inning of a one-run ballgame with his customary relentless stream of fastballs.

“Doooooooooooooo! Doooooooooooo!”

The chants comforted the Washington Nationals’ new closer. He heard them on the mound in Oakland, where he became a fan favorite with the Athletics over five-plus seasons until he was traded in mid-July. It made him feel good.

“Plus, if I ever screw up, it doesn’t sound like they’re booing,” Doolittle said. “So I got that going for me.”

They didn’t boo Doolittle because he didn’t screw up — thanks in part to Andrew Stevenson’s diving catch down the left field line to rob the Miami Marlins’ Dee Gordon of a game-tying hit in Washington’s 3-2 victory. He hasn’t screwed up since joining the Nationals, at least not enough to elicit jeers. Neither have Ryan Madson and Brandon Kintzler, the two other relievers Washington acquired before the nonwaiver trade deadline to repair a broken bullpen.

Since the trio joined forces in Miami on Aug. 2, two days after a last-minute deadline-day deal for Kintzler, they’ve combined for a 1.57 ERA and 0.913 WHIP (walks plus hits per inning pitched) across 23 innings. Doolittle has allowed four earned runs over 10 innings and converted his seven save chances. Madson has logged eight scoreless innings. Kintzler has tallied five. Their performances have instilled confidence in the late innings. Anxiety and dread no longer permeate the dugout in close games. The Nationals expect to win those tight contests now, as a first-place club should.

“Everybody feels a lot more comfortable,” Manager Dusty Baker said.

Baker has deployed the three pitchers in the same order when the Nationals have held a lead entering the seventh inning: Kintzler in the seventh, Madson in the eighth and Doolittle to finish it off. The formula is 3 for 3 with three scoreless efforts so far. Baker, however, anticipates the sequence varying down the stretch to avoid overusing any of the three; it just so happens they’ve all been available and the matchups warranted the order when they have. He views the roles as interchangeable. He also has a statistical milestone in mind.

“When Doolittle is not available to close, I’d like to get Kintzler . . . two more saves for 30,” Baker said. “So I plan on getting that before the year ends.”

While Doolittle had some closer experience and Madson relishes the eighth inning, Kintzler has required some adapting and an ego check. The right-hander was enjoying an all-star season as the Minnesota Twins’ closer before they traded him, accumulating 28 saves in 32 attempts — more than Doolittle has ever compiled in a single season. His dominance in a Nationals uniform suggests he is capable of that role with the new club, but the former independent league player insists he is content in the seventh inning and anywhere else he’s needed.

“It’s definitely a little different adjustment as far as adrenaline and focus,” Kintzler said after throwing a scoreless seventh inning Thursday. “When I was younger, LaTroy Hawkins told me that, ‘We’re closers of our own inning.’ So I always try to take that approach as far as no matter what inning I’m pitching in.”

However they are utilized, the trio provide three unique looks. The left-handed Doolittle peppers the strike zone with a lively mid-90s fastball that has drawn comparisons to the one Billy Wagner wielded. Madson is a right-hander who can dial it up close to 100 mph and is averaging 9.9 strikeouts per nine innings. Kintzler relies on a sinker to generate groundballs and doesn’t miss as many bats as the conventional late-inning shutdown reliever.

“I like that aspect of it,” Madson said. “It’s kind of like when I use to pitch behind Jamie Moyer. It was like the hitters were so late.”

It worked for Madson on Thursday, when he struck out two Marlins in a perfect eighth inning. Doolittle, the “Doooooooo!” chants, and another win followed .