Carlos Beltran singled home the winning run with two outs in the ninth inning and the Mets rallied to beat the Chicago Cubs 7-6 last night for a huge win that halted their late-season slide.

After trailing by three runs in the seventh, New York fought back in the rain to move within one game of NL East-leading Philadelphia with three to play. The Mets began the night tied with Milwaukee atop the wild-card standings.

Rich Harden pitched six solid innings in his final playoff tuneup for the NL Central champions and lightly used rookie Micah Hoffpauir went 5-for-5 with five RBIs and his first two major league homers — including a tiebreaking shot in the seventh off Ricardo Rincon that gave Chicago a 6-3 lead.

But the Cubs, resting most of their stars, couldn’t hold on.

Pitching what could be his final game for the Mets, Pedro Martinez left to a warm ovation with the score tied 3-all in the seventh. He pointed to the crowd and raised his first in the air.

After he was gone, New York tied it in the eighth on big hits by a pair of unlikely players: spare part Ramon Martinez and third-string catcher Robinson Cancel.

Jose Reyes singled off Kevin Hart (2-2) to start the ninth and swiped second for his third steal of the game as David Wright fanned for the second out. Carlos Delgado was intentionally walked and Beltran lined a 2-0 pitch off the glove of a diving Hoffpauir at first base.

The ball trickled down the right-field line as Reyes scored easily, giving the Mets their second victory in six games since they grabbed the division lead with a victory last Friday at Atlanta.

Beltran was mobbed by soaked teammates near first base, a sigh of relief — for one night, at least — as New York tries to avoid its second consecutive September collapse.

Cancel doubled leading off the seventh and scored on Reyes’s grounder. Then, with two outs and none on in the eighth, New York hit four straight singles to tie it.

Ramon Martinez, making his first start for the Mets after a helpful performance off the bench Wednesday, cut it to 6-5 with a single. Cancel, added to the lineup because of Brian Schneider’s aching back, lined a 1-2 pitch to right off Bob Howry.

Kosuke Fukudome’s strong throw home was up the line but it arrived ahead of Ryan Church, who danced around catcher Koyie Hill on the wet dirt. With both players struggling to maintain their footing, Church slipped to the ground, then made a desperate lunge and touched the plate with his hand for the tying run.

Hill threw his arms up in disbelief and the crowd responded with a thunderous roar. Shea Stadium shook as fans jumped up and down.

Joe Smith (6-3) escaped a jam in the top of the ninth, and the Mets rebounded from a demoralizing, 10-inning loss Wednesday night.

***

DODGERS CLINCH NL WEST The Dodgers clinched their first NL West championship in four years yesterday without lifting a bat.

Entering the day with a magic number of one, the Dodgers got what they needed when the second-place Arizona Diamondbacks lost 12-3 at St. Louis in the afternoon. That was several hours before Los Angeles faced the San Diego Padres in its final home game of the regular season.

Manny Ramirez found out the Dodgers officially qualified for the playoffs from a reporter after he entered an elevator to the team’s clubhouse with teammate Pablo Ozuna about an hour after the Diamondbacks lost.

“It’s good, but it’s just the first step,” said Ramirez, who has played so well since joining the Dodgers less than two months ago that there’s been MVP talk. “We’re happy, but we’re not going to go crazy about it. The goal is to go to the big dance, the World Series. This is not a championship yet.

“Not a lot of players get a chance to go to the playoffs in their career. I’ve been blessed. You want to win it all. That’s when you get that feeling you can’t describe, like we had in Boston.”

The Red Sox won their first World Series in 86 years in 2004, with Ramirez winning the MVP award, and won it again last year. But Ramirez wanted out a few months back, and got his wish, being sent to the Dodgers at the trade deadline.

“The sky’s the limit. You never know,” he said of the Dodgers’ chances. “We’re a pretty good team. Anything can happen.”