New York Mets pitcher Noah Syndergaard (34) throws against the...

New York Mets pitcher Noah Syndergaard (34) throws against the San Francisco Giants during the second inning of a baseball game in San Francisco, Sunday, Sept. 2, 2018. (AP Photo/Jeff Chiu) Credit: AP/Jeff Chiu

SAN FRANCISCO — All it took was 10 pitches in the first inning for Noah Syndergaard to tell catcher Tomas Nido — with his actions, not his words — it was going to be a good day.

A first-pitch fastball that turned into a pop-out by Gregor Blanco. A 2-and-2 changeup to Joe Panik for a groundout. A 92.9-mph slider and a 91.1-mph changeup — both whiffs — to Evan Longoria.

Syndergaard had it all working Sunday, so Nido came away unsurprised at the result: the righthander’s first career complete game, a two-hitter with 11 strikeouts and one walk in the Mets’ 4-1 win over the Giants.

“It was just how quick it happened and his presence,” Nido said. “From the bullpen [onward], he looked like he had command of all his pitches and was throwing them right where he wanted to .  .  . Every pitch was with a purpose.”

Michael Conforto smacked a two-run home run to center in the second, his 20th of the season, and Jeff McNeil hit a two-run single in the eighth. The homer was another positive sign for Conforto, who after an up-and-down first half is hitting .261 with a .343 on-base percentage and .484 slugging percentage since the All-Star break.

But Syndergaard was the star. The only run off him came on a sacrifice fly in the third after Alen Hanson’s sinking liner to right skipped past a diving Brandon Nimmo for a triple. The only baserunner in the final five innings came on first baseman Jay Bruce’s throwing error.

The game plan was for Syndergaard to mix in all of his pitches early, a prescription simplified by his good feel for all of them. According to MLB’s pitch-tracking technology, only 39 percent of his pitches were fastballs — four-seamers and sinkers — significantly lower than his average of 54 percent.

“Their game plan was to come out and jump on the fastball,’’ Syndergaard said, “and I didn’t allow them to do that.”

When Syndergaard blew a 98.6-mph fastball past Chase d’Arnaud on his 100th pitch to end the eighth, he walked down the dugout steps to Mickey Callaway’s quick question: “How are you feeling?” Said Syndergaard: “I assumed that’s what the game plan was. I had plenty of juice in the tank.” Nobody was moving in the bullpen. He was getting a chance to be his own closer, and he ended it with a 99-mph sinker to Longoria for a swinging strike three.

“It’s an amazing feeling. It’s a beautiful day in San Fran,” Syndergaard said, noting that he likes pitching here because he doesn’t sweat as much. “I have my family here. I couldn’t have asked for a better day.”

It was a much-needed effort in an underwhelming season, including a 4.74 ERA in August.

“He needed it for a lot of reasons,” Callaway said. “One, to understand that he’s still working on things, but the time to work on things is in between starts, not when you’re out there competing.”

Said pitching coach Dave Eiland: “You trust the work you put in during the week between starts, your side sessions. We get all that straightened out, boom, boom, boom, boom, and you trust it to take it into the game.”

That has been among the toughest lessons for Syndergaard this year: Don’t try to tinker with his mechanics in-game.

“It’s something I’ve been trying to work on all season. It’s kind of hindered me a little bit,” he said. “I told myself at the end of August that I have a fresh, clean slate to start September and take myself into the offseason. I took that to heart and just want to finish the season strong.”

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