NEW YORK — The good vibes lasted only a day.

The Giants dropped back below .500 with a 12-6 blowout loss to the New York Mets on Saturday evening at Citi Field. San Francisco (55-56) has now lost 11 of their its 14 games to begin the second half and are currently 6.5 games back of the San Diego Padres the final NL Wild Card spot.

Tyler Rogers, who appeared in 392 games for the Giants, faced his old teammates as he made his Mets debut. Rogers allowed a single to Heliot Ramos on a grounder that bounced off first base but pitched a scoreless seventh inning.

Rogers wasn’t the only player on Saturday who had success against his former team. Dominic Smith, who spent the first six seasons of his major-league career, hit a two-run homer of Kodai Senga, his third home run of the season. On Friday night, Smith drove in the winning run in the top of the 10th with a single up the middle.

Despite the homer, Smith made a curious defensive mistake in the bottom of the fourth.

With runners at first and third with one out, Francisco Lindor laid down a push bunt right at Smith. Brett Baty, the runner on third, immediately broke home. If Smiht threw to the plate, the Giants would’ve likely gotten the out. Smith instead tried to throw to second, but held onto the ball because no one was covering the base. Smith turned back to first for the force out, but Lindor was already crossing first. The Mets took a 5-4 lead, a lead they’d never relinquish.

Kai-Wei Teng was roughed up by New York’s potent offense, allowing five earned runs over 3 1/3 innings with three walks to four strikeouts. Three of those runs came in the first when Pete Alonso eviscerated a three-run homer, bringing himself within two home runs of tying Darryl Strawberry’s record of 252 for the most in franchise history.

Following Teng’s departure, the Mets continued attacking the Giants’ bullpen. Spencer Bivens allowed two runs during his lone inning of work on a pair of RBI singles from Brandon Nimmo and Francisco Lindor, while Tristan Beck allowed five runs over two innings that put the game out of reach.

Outfielder Grant McCray bolstered his case to receive more playing time in right field following the trade of Mike Yastrzemski, totaling a single, a triple and an RBI. Shortstop Willy Adames hit a two-run homer, his 17th of the season, in the top of the ninth as the Giants trailed by eight runs.