MLB

METS PHILLIN’ NOOSE TIGHTEN

Two homers in the first inning gave the Mets an early lead last night, and a third homer soon followed. The Mets built a big early cushion, and emergency starter Philip Humber was delivering in his major league debut.

But the Mets’ emergency became much worse as the game continued.

A few innings later, Humber and the Mets’ bullpen crashed en route to a staggering collapse. The Mets’ playoffs hopes are in jeopardy, the season on the brink of complete disaster.

The Mets blew a five-run lead last night at Shea, getting swept by the Nationals, 9-6. The Phillies beat the Braves, and the Mets’ NL East lead is down to one with four games remaining.

The reeling Mets have dropped nine of 13.

“Seems to me we’re all waiting to lose,” Paul Lo Duca said. “Better change quick or in five days we’re all going to be home for the winter.”

The embarrassing Washington sweep leaves the Mets with a game tonight against the Cardinals – Pedro Martinez is on the hill – and then a final three-game set against Florida. Philly will host Atlanta tonight, then finish up with three against Washington.

“There’s no room for error,” David Wright said. “So from here on out, it’s a four-game season. We’ve played 158 games and they don’t mean anything right now. These next four games are going to determine whether we go to the playoffs. It’s simple.”

No team has held a seven-game lead with 17 to go and not won the division or league, but the Mets are in that potential position. As for the wild card, the Mets are tied with the Padres, 11-3 winners over the Giants last night.

The Mets jumped out to a 5-0 lead in the first three innings, thanks to two homers from Carlos Beltran and one from Moises Alou.

Humber, making his first major league start, tossed three shutout frames to open the game.

“We did everything we wanted to do tonight,” Wright said. “We jumped on them early. We added on. We just couldn’t stop the bleeding.”

Beltran said the game was “unbelievable,” calling it “a great start and a terrible finish.” He was actually a little off, the terrible part started in the middle innings.

Humber gave up two runs in the fourth, and the Mets later blew a 6-2 lead in the fifth when Washington put up five runs off Humber, Joe Smith and Pedro Feliciano.

“As good as our bullpen was early,” Billy Wagner said, “we’re that bad right now.”

For the Mets, who didn’t score after the fourth inning, the risk to starting Humber backfired a bit, though the other option (pitching Dave Williams) was hardly a better choice. Humber began impressively, but lasted four-plus innings, allowing five runs.

Humber, who hadn’t pitched since Sept. 11 for the Mets and hadn’t started a game since Aug. 27 for Triple-A New Orleans, carried his 5-0 lead into the fourth. But then the 24-year-old began to get hit. He served up Ryan Church’s two-run homer, and after the Mets regained a 6-2 edge, Humber put the first three Nationals on in the fifth, thanks to a walk, single and RBI double.

“I just couldn’t make the right pitches at the right time in that fifth inning,” said Humber, who admitted his legs began to run out of steam that inning.

Willie Randolph summoned Smith, who gave up back-to-back singles as Washington cut it to 6-5. Feliciano then struck out Church but surrendered Wily Mo Pena’s two-run double, putting the Nats up 7-6.

“We have no more options,” Beltran said of the Mets’ dwindling NL East lead. “Just winning ballgames.”

mark.hale@nypost.com

Nationals 9 Mets 6