Jacob deGrom put Mets fans at ease with a bevy of triple-digit heaters.

Hopefully clear of the arm woes that interrupted his past two starts, the two-time NL Cy Young Award winner is back to dominating hitters — and the record books.

DeGrom shouldered the load for New York in his return from another injury scare, pitching one-hit ball over five scoreless innings as the Mets beat the Atlanta Braves 4-2 Monday to open a doubleheader.

DeGrom (7-2) didn’t allow a hit in the seven-inning game until Mets outfielders misplayed a fly ball with two outs in the fifth, letting it fall for a ground-rule double. DeGrom threw 70 pitches, 15 of them over 100 mph, with two walks and six strikeouts.

“Felt good,” deGrom said. “I think that’s why we decided at that 70-pitch mark to say that was enough, didn’t want to overdo it.”

Jeff McNeil came off the injured list and singled as a pinch-hitter for deGrom during New York’s three-run fifth inning. He scored on Dominic Smith’s three-run double.

Ozzie Albies hit a two-run homer off Seth Lugo for the Braves, who had won three of four but were playing their second doubleheader in two days. Left-hander Kyle Muller (0-1) pitched one-hit ball over four innings, leaving with a 1-0 deficit in his first big league start.

“He threw the ball extremely well,” manager Brian Snitker said. “Had a good breaking ball, kept his composure, everything was really good.”

Mets closer Edwin Díaz finished up the two-hitter, pitching the seventh for his 15th save in 16 chances.

DeGrom has thrown 30 consecutive scoreless innings, 2 2/3 shy of R.A. Dickey’s franchise record set in 2012. His 0.50 ERA is the lowest by a pitcher through 12 starts in major league history. Opponents are hitting .113 against him, the lowest average against any pitcher in a 12-game span since at least 1901, with a minimum 70 innings.

Two days after his 33rd birthday, deGrom came out firing in his first start since his previous two outings were cut short by arm trouble. The right-hander was pulled after three perfect innings against the Cubs last Wednesday with shoulder soreness, and he left the outing prior to that June 11 against San Diego with flexor tendinitis in his right arm.

DeGrom put nervy New York fans at ease by striking out Ronald Acuña Jr. with a 100 mph fastball to start the game. He struck out two during a perfect first inning and has retired 34 consecutive first-inning hitters, the most in the majors since at least 1961.

DeGrom has thrown 154 pitches at least 100 mph this season. That’s most in baseball among starting pitchers — Tampa Bay’s Shane McClanahan was second entering Monday with 14.

“He’s on another level,” Snitker said.

Smith’s fly dropped on the warning track in the fifth between center fielder Albert Almora Jr. and left fielder Dominic Smith. The outfielders appeared to miscommunicate on the catchable ball, which bounced over the wall for a ground-rule double.

“Almora came in after the inning and was apologizing to everyone in the dugout,” manager Luis Rojas said.

Heredia was on first for Smith’s fly and would have scored if the ball didn’t skip out of play. DeGrom stranded both runners by inducing a popup from pinch-hitter Pablo Sandoval.

DeGrom thinks he injured his shoulder batting, and he planned to refrain from swinging. With runners at second and third in the second inning, the left-handed hitter couldn’t help himself and tried to slap Muller’s pitch to left field. He popped up to center.

The lefty-hitting deGrom’s average dropped to .407. He has six RBIs this season compared to four earned runs allowed.

“That’s something we’re going to have to discuss,” deGrom said. “I’ve said it before, I do enjoy hitting, but my main focus is to be out there on the mound.”

STICKING TO THE PLAN

DeGrom was the first pitcher inspected as part of Major League Baseball’s crackdown on foreign substances. He passed.

Fans booed loudly when plate umpire Ben May halted deGrom on his way off the field after the first inning. Crew chief Ron Kulpa jogged in from third base and asked deGrom for his glove and hat, and deGrom chuckled as he handed them over. Kulpa also asked deGrom to undo his belt buckle and checked for goop there, too.

Cleared by Kulpa, deGrom walked on to the dugout, laughing with catcher Tomás Nido about the exchange. Pitchers from both teams were checked throughout the game.

“Honestly, I didn’t mind it,” deGrom said. “It was quick and it went pretty easy.”

TOUGH TO HANDLE

Acuña struck out in bizarre fashion in the sixth. He was initially awarded a hit-by-pitch on a 1-2 fastball from Seth Lugo, but the Mets challenged. Umpires ruled the ball hit the handle of Acuña’s bat for a foul tip, and because catcher James McCann caught it, it counted as a third strike.

TRAINER’S ROOM

Mets: McNeil hadn’t played since May 16 because of a left hamstring strain. ... C Tomás Nido was hit on the right wrist by a pitch in the opener and was replaced a half-inning later by James McCann. X-rays were negative. ... RHP Robert Gsellman was placed on the 10-day injured list with a right lat strain. ... RHP Jeurys Familia was added to the 10-day injured list between games with a right hip impingement. ... LHP Stephen Tarpley was recalled from Triple-A Syracuse as New York’s 27th man for the twinbill.

Braves: Muller was Atlanta’s 27th man.

UP NEXT

Braves RHP Ian Anderson (4-3, 3.58) could become the first New Yorker to beat the Yankees and Mets in the same season when he starts the nightcap. Mets RHP Jerad Eickhoff will start for his first appearance this season.