For the better part of a month, Carlos Delgado was in a funk. His guesses at the plate were off, his timing was shot, his swing had gone bad.

Only his words were far stronger.

But that all changed in the last half-dozen games. The Mets first baseman worked his way out of whatever malaise plagued him and back to his early-season form. And this six-game stretch, which continued last night in a 10-8 win over St. Louis, was a tantalizing reminder of what he can be.

“He’s still one of the best hitters in the game and what he’s doing shows it,” Willie Randolph said. “Once he gets in a groove, he can be nasty. I always say you may go through a funk, but when you come out make sure you get some payback. Hopefully it’s time to get payback.”

Delgado has taken his revenge, first on the Rockies, now on the Cardinals. First came a two-homer display (including a grand slam for career home run No. 400) Tuesday against Jeff Weaver, then last night’s 2-for-5 game, with two doubles, two runs scored and an RBI.

“It’s about getting the pitch you want to hit,” Randolph said. “Mechanically, he was getting out in front. Lately he’s just been staying back better.”

That was demonstrated in his first-inning at-bat, when he stayed back on a 1-2 Mark Mulder curveball, lacing an RBI double to right. Delgado added another double to left-center in the fourth, scoring one batter later.

He’s 11-for-23 with nine runs scored, five home runs and 12 RBIs in his past six games, all Mets wins. Not bad for a guy who was in an 0-for-17 slump until he snapped it Aug. 16 in Philadelphia. The next day he went deep twice, his first homers in 63 plate appearances covering 17 games to July 30.

“I wasn’t swinging good. I’m not going to lie. For a couple months I was struggling. Sometimes your swing goes [bad], and you just have to find a way to get it back,” said Delgado, who is the fourth man with 10 straight 30-homer seasons.

“It was just timing. You might swing too early when you’re not covering your strike zone, not getting to the fastball. Your natural reaction is to jump out there, and next thing you know you can’t hit the fastball or the breaking ball. But at the end of the road trip I was putting together good at-bats.”