The 23-year-old first base prospect launched the first pitch he saw into the upper deck in right field for his second homer of the season Wednesday night, and the Mets went on to a 5-3 victory over the San Francisco Giants.
Smith's drive came two nights after his overaggressive mistake in left field cost New York the series opener.
"You kind of want to have a short memory, obviously, because we have games every day," Smith said. "But we're still human."
Jose Bautista also went deep for New York. Jeff McNeil tripled and singled his first two times up to set a Mets rookie record with a hit in eight consecutive at-bats. The 26-year-old second baseman grounded out in his next chance at the plate.
Smith charged in hard from left field and barreled into shortstop Amed Rosario on what should have been a routine popup Monday night, knocking the ball loose and allowing San Francisco to score the decisive run in the 13th inning.
"I care about the team, I care about the fans and I don't want to let anybody down," Smith said. "You do think about that stuff and you do feel bad, but you've kind of just got to forget about those things and rebound from it and play hard."
Smith's leadoff homer in the second off Giants starter Casey Kelly (0-2) gave New York a 1-0 lead.
McNeil then surprisingly swung away at a 90 mph fastball on a 3-0 count for a single to right that produced the second run of the game.
"I thought that was a good time to do it," McNeil said. "Runner on third base, two outs, I know he was trying to throw one in there."
Frazier made it 3-0 with a ground-rule double that bounced over the left-center wall, sending McNeil back to third base after a replay review.
Syndergaard (9-3) started out on a roll, retiring his first six batters before permitting consecutive singles to begin the third. Steven Duggar had an RBI groundout and Joe Panik added a run-scoring single to cut it to 3-2.
Syndergaard allowed two runs and five hits while walking one and striking out six. Paul Sewald got two outs for his first major league save.
New York got to Kelly again in the fourth on Bautista's 11th homer, a two-out drive to center that made it 4-2.
Kelly gave up seven hits and four runs -- two earned -- over six innings in his second start for San Francisco this season. He struck out four and did not issue a walk.
"He got us somewhat deep in the game, six innings there," Giants manager Bruce Bochy said. "Could have come out a little better -- we didn't play great behind him -- but he battled and kept us in the ballgame."
Frazier answered in the bottom half with a solo shot to left, his 13th homer of the year.
The Giants have dropped six of seven.
SCHOOL'S IN SESSION
San Francisco outfielder Andrew McCutchen had a scheduled night off amid speculation he was held out of the lineup due to an imminent trade. "Waivers, clears or revocables -- I don't know what that stuff means," McCutchen said. "I don't get it. I've got a better chance understanding trigonometry. ... Until somebody calls or whatever happens, then cool. But I have to try and just keep it simple and don't even focus on what that stuff means and just play baseball."
Giants: RHP Jeff Samardzija (right shoulder inflammation) made a rehab start with Double-A Richmond. He pitched four scoreless innings, allowing one hit. He walked one and struck out one.
Mets: OF Jay Bruce, on the disabled list since June 19 with a sore right hip, homered and had an RBI single in his latest rehab game with Class A St. Lucie. He started at first base. Bruce is expected to return to the club Thursday and be activated for Friday's series opener against Washington. ... David Wright played third base for seven innings with St. Lucie and went 0 for 3 at the plate.
Giants: LHP Madison Bumgarner (4-5, 3.05 ERA) makes his 15th start of the season. Bumgarner, who is 5-0 with a 0.47 ERA in five starts at Citi Field, last faced New York in the 2016 NL wild-card game, a shutout performance that sent San Francisco to the NLDS.
Mets: RHP Jacob deGrom (8-7, 1.71) is coming off his first complete game of the season last Saturday at Philadelphia. DeGrom is 4-1 with a 3.12 ERA over six career starts against San Francisco.
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