Will Mets be flying high when they leave Philly?

They are once again the top two teams in the National League East, even though it's not even a month into the season.

But the mere fact that the Mets, coming off a 9-1 homestand, now sit half a game ahead of the Phillies as the teams kick off a three-game set at Citizens Bank Park in Philadelphia tonight means that this is a rivalry that has relevance again.

"I'm kind of anxious to see it when we're hot, when the opposition is hot, and see how it goes then," said Jerry Manuel, who readily admitted that the Cubs, Braves and Dodgers weren't exactly at their best when the Mets rolled over them at Citi Field. "I'd like to see how we respond in these games."

The Phillies may be the reigning best team in the league, but they're not exactly at their best right now - in fact, their season has been the exact opposite of the Mets' so far. Philadelphia got off to a great start (8-2) but has struggled of late, going 4-7 in its last 11 games, having salvaged a rough 4-5 road trip with a 7-6, 12-inning come-from-behind-win in San Francisco on Wednesday.

But the Phillies do have Roy Halladay going Saturday. His first season in the NL is going as well as his seasons in Toronto went: Halladay is 4-1 with a 1.80 ERA and 33 strikeouts.

"What's amazing about him is how he commands the strike zone with quality pitches," said Jason Bay, who is 5-for-18 with two homers against Halladay. "It's perceived as easy to throw strikes if you're grooving an 85-mph fastball. But he's throwing quality pitches for strikes any time he wants. The pitch you see 0-and-0 is the same pitch you're going to see 0-and-2."

If the Mets were still scuffling, the prospect of facing Halladay in the middle game might have been a downer. But the Mets have an answer for Halladay Saturday in Mike Pelfrey, who's had an even better April than the Phillies' ace.

"When you're up against guys that are great, it brings the best out in you," said Pelfrey, who is 4-0 with a 0.69 ERA and a 24-inning scoreless streak. "You know he's going to be good. If you want to win, you have to be good too."

And Johan Santana's no slouch either. He pitches Sunday; Jon Niese goes Friday night for the Mets, who bring the superior pitching staff into the series.

The Mets may not bring the better lineup, but their offense drastically improved during their franchise record-tying homestand. The Mets hit only .262 during the 9-1 run, but they were .293 with runners in scoring position - for the season the Mets are hitting just .223 with runners in scoring position.

This is the best possible scenario Mets players could have envisioned after they trudged home from St. Louis with a 4-8 record.

"We're feeling really good about ourselves," Jeff Francoeur said. "There's no reason to assume other than that we're going to keep playing well and win the series down there."