MLB

Finally, Pelfrey so good it’s sick

THAT’S BETTER: Mike Pelfrey, who allowed one run in seven innings, picked up his first win of the season in the Mets’ 4-1 victory over the Diamondbacks last night at Citi Field.

THAT’S BETTER: Mike Pelfrey, who allowed one run in seven innings, picked up his first win of the season in the Mets’ 4-1 victory over the Diamondbacks last night at Citi Field. (Getty Images)

On a night he was sick to his stomach, Mike Pelfrey brought his “A” game to Citi Field — “A” as in accountability.

Accountability is a beautiful thing. It’s clear under Terry Collins that the Mets’ manager is going to let results dictate playing time and the pitching rotation.

There are no free rides. Going into his start last night, Pelfrey needed to put on a better show than he has so far this season. He went into the game against the Diamondbacks with an 0-2 record and an unsightly 9.72 ERA.

He looked like he didn’t belong in the majors.

Pelfrey then went out and did what the Mets have been expecting him to do all April. He was magnificent for seven innings, allowing just five hits and one run while striking out four. Ike Davis made it all pay off with a two-run home run in the seventh to lift the Mets to a 4-1 win over the Diamondbacks.

BOX SCORE

All this after Pelfrey allowed a leadoff triple and a walk and worked out of the first inning jam. All this despite the fact Pelfrey was so sick he couldn’t keep down what was ailing him in the sixth inning on the mound.

“I started getting ready for the game and I started getting real hot and started sweating,” Pelfrey said. “Felt it in my stomach, head and chest. I went out to the bullpen, my bullpen wasn’t very good. I kept coughing. In the sixth inning I puked in my mouth and swallowed it on the mound.”

OK, Big Pelf. That’s a little TMI.

But that’s also toughing it out. That’s what the Mets have been waiting to see from their big right-hander. Being sick, Pelfrey said, made him more effective because he wasn’t overthrowing.

Pelfrey is supposed to be the Mets’ No. 1 starter and last night he finally acted like one. Pelfrey had not made it through six innings this season. The Mets had lost all four of his previous starts.

“That first inning set the tone,” Collins said. “They could have jumped out to a big inning but [Pelfrey] just said, ‘Not tonight.’ ”

With Chris Young returning Tuesday from biceps tendinitis and today’s starter Dillon Gee looking good, the heat was on Pelfrey. Another bad start and he could have been looking at a trip back to the minors to work it all out.

It worked for Cliff Lee. The Mets cannot afford to sit around and wait for anyone. They must live by the Bill Parcells adage: You are what your record says you are.

The key to pitching at Citi Field is throwing strikes on the outer half of the plate. The ballpark is too big to do anything else. If you work the outer half, it is a pitcher’s paradise.

Pelfrey, a fly ball pitcher, needed to make the park work for him and he did just that, inducing 13 outs through the air. That shows he had more life on his fastball and he also worked well with catcher Mike Nickeas.

Among all pitchers who have started at least four games this season, the right-hander’s 9.72 ERA was the third worst. Last April Pelfrey was tremendous, going 4-0 with a 0.69 ERA.

Pelfrey had relied too much on his slider this season.

“And that has gotten him in trouble,” Collins said. He got back to establishing his fastball and working off that pitch.

“I never doubted he was the guy to pitch opening day,” Collins said. “I knew he deserved it. There were times I thought I put too much pressure on him because of that, I really did. I loaded him up with having a huge task, having to face the other team’s No. 1 guy. That’s why I think tonight was a big step for him. If he can continue like this I don’t care who he faces he’s going to get people out.”

On a night he wasn’t feeling his best, Pelfrey was at his best. Give him an “A” for accountability.

kevin.kernan@nypost.com