Mets pinch hitter Brandon Nimmo reacts as he rounds the...

Mets pinch hitter Brandon Nimmo reacts as he rounds the bases on his walk-off three-run home run against the Philadelphia Phillies during the tenth inning of an MLB baseball game at Citi Field on Wednesday. Credit: Kathleen Malone-Van Dyke

Jacob deGrom dominated again Wednesday night, and this time the Mets made something of it, beating the Phillies, 3-0, on Brandon Nimmo’s 10th-inning, pinch-hit, three-run walk-off home run.

Lowering his ERA to an MLB-best 1.68, deGrom struck out seven and scattered five hits and one walk, as efficient as possible against a Phillies lineup notorious for making starters work.

DeGrom returned to the mound for the eighth inning at 100 pitches and set Philadelphia down in order, the finishing touches on one of the Mets’ all-time great first halves.

What does deGrom have to show for it? A 1.44 ERA in 10 no-decisions, an All-Star selection, a Cy Young Award case and a rising trade value that the Mets don’t appear particularly interested in cashing in on. His five wins are second on the team. Reliever Robert Gsellman picked up his sixth with a scoreless top of the 10th inning.

DeGrom’s ERA, which is actually 1.678, is second best in Mets history before the All-Star break. The only hurler better: Dwight Gooden, at 1.677 in 1985.

That left manager Mickey Callaway with one conclusion, stated with the type of conviction that he asks all of his pitchers to throw with.

“He should be starting the All-Star Game,” Callaway said. “That’s how I feel about it. There’s no doubt in my mind. If he’s not, that’s the wrong decision.”

DeGrom has as strong a case as anybody. The Nationals’ Max Scherzer, who has a 2.33 ERA and starts against the Mets on Thursday, is the hometown ace and the other top candidate to get the ball for the National League at Nationals Park on Tuesday.

“That decision is not up to me,” deGrom said. “Of course, I’d like to start it, but we’ll just see what happens.”

In his typical understated tone, deGrom said Wednesday was the same as any other night, trying to attack hitters and give 100 percent and keep his team in the game. He did that in part by holding the Phillies to 0-for-4 with runners in scoring position. Opposing hitters have a .122 average in those situations this year against deGrom.

That came in handy because the Mets, again, did not offer him any run support. They had two hits in the first nine innings. Of deGrom’s 19 starts, the Mets have scored three runs or fewer 12 times.

“The most impressive part is his ability to not worry about the lack of offense behind him, to stay even-keel and just keep on doing the things he knows he has to do to have success, whether he’s getting wins or not,” Callaway said. “I think it’s pretty impressive. Most people can’t just sit there and weather the storm like that.”

Said deGrom: “When I’m out there, I try to think it’s 0-0 the whole time. Which it was tonight.”

DeGrom increasingly finds his name next to Mets greats. His 16 consecutive starts of allowing three or fewer runs is the Mets’ longest single-season streak since Gooden’s 1985. His 149 strikeouts are the fourth most pre-All-Star break in franchise history behind Gooden (153 in 1985), David Cone (154 in 1992) and Tom Seaver (178 in 1970).

“I try not to look at that stuff,” deGrom said. “I just try to focus on what I can control, and that’s going out there and throwing the baseball kind of close to where I want it.”

And yet deGrom can only do so much. The Mets (37-53) are 13 1⁄2 games behind the Phillies and Braves, who are tied for first in the NL East at 51-40.

“Nobody is excited with how our first half went,” deGrom said. “We definitely wanted to be in a better situation going into the All-Star break and after the All-Star break, but that’s not what happened.”

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