“In a big game, obviously we liked our chances not having to face him,” Phillies Rhys Hoskins said.

By Mary Cunningham

Hoskins was talking about the Mets’ Jacob deGrom, the major league leader in earned run average, who was scratched from a start yesterday because of a steady rain.

Hoskins hit a two-run homer in the first inning against the rookie Corey Oswalt, but the visiting Phillies’ Vince Velasquez allowed a tiebreaking three-run homer by Michael Conforto in a four-run fifth inning that propelled the Mets to a 6-4 win.

Since the Phillies moved a season-high 15 games over .500 with a four-game sweep of Miami that ended Aug. 5, they have gone 10-20. They are winless in 10 series, losing nine — including seven in a row.

“Of course that’s a missed opportunity,” Hoskins said. “Not because it wasn’t deGrom and we didn’t beat somebody else. Just another series that seemed to slip away.”

The Phils led the National League East before play Aug. 12 but wake up this morning four and a half games behind first-place Atlanta. The Phillies trailed by the same margin for the second wild card with three weeks left.

After a loss as dismal as Sunday’s weather, manager Gabe Kapler said “we need to turn the page quickly” more often than a speed-reading instructor.

“Things kind of just got out of hand,” Velasquez said. “Missing spots kind of all game. Conditions kind of got the best of me, and can’t let that happen.”

Conforto tied a career best with four runs batted in and made a fine catch. The rookie Jeff McNeil had his second straight three-hit game, his fifth over all, raising his average to .340 as the Mets took two of three.

Mets Manager Mickey Callaway decided just before a 27-minute rain delay at the start that he wouldn’t pitch deGrom.

“We kind of approached Jacob about it, said, Hey, there’s a good chance you could start this game and it could be one inning or two innings. We could get a long delay and probably bang for the rest of the day,” Callaway said.

Making his ninth start, Oswalt allowed his 13th home run in 53 innings. Hoskins went deep for the third straight game and reached 30 home runs in a season for the first time.

Velasquez (9-11) gave up Amed Rosario’s eighth triple of the season leading off the bottom half, and Conforto followed with a run-scoring infield single — ending Velasquez’s streak of 14 consecutive scoreless first innings.

Dropping to 1-3 in his last six starts, Velasquez failed to get an out in the fifth. Pinch-hitter Dominic Smith doubled, Rosario was hit by an 0-2 pitch, McNeil lashed a tying opposite-field single to left and Conforto drove the next pitch for his 23rd homer, an opposite-field shot just over the left-field wall. The ball originally was called a double but was changed after a review of less than a minute.

Velasquez said he thought the Phillies were lucky to still have a chance to reach the postseason.

“With us being the young team that we are, no one expected us to go this far,” he said. “I think all of us as individuals are pretty content in where we are right now, but we’re capable of doing a lot more and doing better.”

In a game played before what appeared to be fewer than 10,000 fans from an announced crowd of 24,153, the rookie Drew Gagnon (1-1) pitched two hitless innings for the win in his first big league appearance since his debut against the Phillies on July 10.

Wilson Ramos had a sacrifice fly off Drew Smith in the sixth, but Austin Jackson restored a three-run lead with an R.B.I. double in the seventh against Hector Neris. Four Mets pitchers combined for two-hit relief over six innings; Seth Lugo got six outs for his second save, allowing a two-out homer by Carlos Santana in the ninth.