Fernando Tatis turned this into an extra special win for the Mets.

Almost left behind on baseball’s scrap heap, the resurgent Tatis homered, doubled twice and drove in four runs as the Mets beat the San Francisco Giants 7-3 yesterday for their sixth straight victory.

“It’s amazing,” Tatis said.

Best known as the only major leaguer to hit two grand slams in a single inning, Tatis delivered the first three extra-base hit performance of his career, the Elias Sports Bureau said.

Tatis’s tiebreaking home run in the seventh inning was timely, too. After the game, the Mets said outfielder Moises Alou had torn his left hamstring and likely was done for the year.

“It’s a good day for Fernando Tatis to have a good day,” general manager Omar Minaya said.

The Mets’ winning streak is their longest since a seven-game string in August 2006. Tatis also contributed in a big way Sunday with a two-run homer in the 12th inning that beat Philadelphia.

Out of the majors since 2006, Tatis was a late arrival in spring training. When he got promoted from the minors in mid-May, the Mets regarded him as a utilityman and possible pinch-hitter.

But the 33-year-old Tatis has proven to be a valuable bat, an adequate fielder and someone who runs well. And with the Mets minus Alou and Ryan Church in the outfield, Tatis could stop the merry-go-round.

“I don’t want to think about taking anyone’s job,” Tatis said. “Whenever they put me out there, I’ll play hard.”

David Wright doubled twice, and scored the go-ahead run in a four-run seventh inning. It was his last bid to earn the final spot on the NL All-Star team — Internet balloting closed shortly after the game.

The Giants ended their scoreless streak at 21 innings, but still lost their fourth in a row. They were held to three hits in each of the three losses to the Mets.

“We just got outplayed. We got outhit, we didn’t play well on defense,” manager Bruce Bochy said. “It was probably our worst series of the year. The Mets, they’re playing well right now. They’re a hot team. We’re not playing well. That’s why we got swept.”

Scott Schoeneweis (1-2) won in relief of John Maine. Tatis hit his fourth homer, a two-run drive into the left-field bleachers off Sergio Romo (0-1) in the seventh.