Before “Win Day” became a common phrase around the Cubs with Yu Darvish last season, Jake Arrieta gave the team the same jolt of confidence whenever he took the ball in his first stint in Chicago.

Arrieta may be three years older now but in his second run with the Cubs, that feeling of confidence remains.

After Tuesday’s win, Arrieta (3-1) has nearly half of the Cubs’ 7 victories this season.

He also has a 2.86 ERA and 1.27 WHIP through his first 4 starts while the rest of the rotation sports a 6.79 ERA and 1.55 WHIP entering play Wednesday.

Simply put: Arrieta has not only delivered in turning back the clock, but he’s emerged as the stopper this pitching staff — and team — really needs right now.

“It’s been nice,” David Ross said. “With where things have been in the starting rotation a little bit and to have a guy that you can lean on a little bit that actually welcomes that kind of feeling or those expectations is nice.

“He carries himself around the clubhouse, when he’s on the mound, around this group with a lot of confidence and it stands out to me. It’s nice to have that solid foundation guy in your rotation.”

When Arrieta first showed up to Cubs camp in Arizona in med-February, he talked about how he felt like he had a lot left in the tank. He also spoke about how important the familiarity was with this coaching staff to change some of the bad habits he picked up with the Phillies due to injury.

That culminated in a lot of work throughout spring training, getting Arrieta back to more of the crossfire delivery that made him so successful in his first go-round with the Cubs.

So far, that’s translated onto the field, too.

“I’m throwing the ball the way I expect to throw it,” Arrieta said. “Things I could do better, for sure. But you take what you have at your disposal and you use it to the best of your ability to try and help the team win.”

The curveball was not at Arrieta’s disposal Tuesday night. That’s normally a pretty big pitch in his arsenal, but he said he didn’t have a good feel for it because the ball was slick in the cold so he resorted to another offering instead.

After rarely using the changeup in his previous few starts, Arrieta threw that pitch 13 times Tuesday night to keep the Mets hitters off balance.

“That’s how it goes,” he said. “That’s why as a starter, it pays off to have more than three pitches at your disposal. In case you have an issue with one or two, you have something else to go to.”

That kind of mental toughness is what the Cubs have come to expect out of Arrieta, who has been a voice of reason in the clubhouse in the early going.

As the Cubs work to put their slow start behind them, Arrieta continues to preach the need to take things one game at a time. Tuesday night, he went out there and walked the walk — including in the batter’s box where a sacrifice bunt and walked helped lead to the team’s 3 runs.

But none of this comes as a surprise for the Cubs.

“We have high expectations for Jake,” Ross said. “I think he has high expectations for himself. He’s been really good so far for us. Jake’s a really good pitcher with a really good track record. His hard work and him being healthy is really, really paying off for us.

“We were able to take advantage of a guy that we knew really well and with him being completely healthy and a couple things that we believed he could do to make himself a little bit better and him putting in that work has really paid off. When he’s right, he’s one of the best in the game, as we’ve seen.”