MILWAUKEE(AP) Brewers hitting coach Dale Sveum had recently told Casey McGehee that there's nothing like the emotional swings they face in baseball. McGehee faced it all in the same inning.

''I experienced them both pretty quick,'' McGehee said. ''It's ironic people start talking about stuff and it happens right away.''

McGehee hit his first career grand slam moments after committing a costly gaffe in the sixth inning and then took out his frustrations on his helmet in the Milwaukee Brewers ' 10-6 win over the reeling New York Mets on Monday night.

''Me and my helmet are going to have to have a sitdown apology session later,'' he joked. ''I might have hurt its feelings.''

J.J. Hardy also went 4 for 4 with a homer and was on base all five times for the NL Central leading Brewers, who have won three of four. Hardy also finally got McGehee to smile a few innings after he dropped a routine pop up.

''I think it even took him a couple of innings to realize what he had done because he was still pretty upset about the dropped pop up,'' Hardy said. ''We were all really excited for him.''

The Mets have lost four straight, falling under .500 (37-38) for the first time since May 5, and not even the previously unflappable Fernando Nieve (3-1) could help. He gave up 11 hits and three runs before being pulled after 3 1-3 innings.

''We're a below average team. Period,'' Mets manager Jerry Manuel said.

McGehee nearly gave New York a way out after giving the Mets life with starter Braden Looper (6-4) cruising and Milwaukee leading 3-0.

With two outs and a man on first in the sixth inning, the Brewers third baseman dropped Fernando Martinez 's routine fly ball when it hit the heel of his glove and dropped harmlessly to the ground , putting runners on the corners.

''You play long enough you're going to have one of those, 'What are you doing moments?''' McGehee said. ''(I) more felt terrible for Looper in that because he was throwing the ball so well. ... I felt like I took the momentum he had going and kind of put it to a halt.''

Brian Schneider hit the next pitch off the wall for a two-run double to cut it to 3-2, but Looper got out of the jam.

In the bottom of the inning, Hardy had his third extra base hit when Martinez tried to make a diving catch on a liner to put men on second and third with one out.

After Ryan Braun popped out and Prince Fielder was intentionally walked, McGehee drove a high fastball from reliever Brian Stokes into the Brewers bullpen in left center field to make it 7-2.

''I'm sure he went up there to try and redeem himself,'' Stokes said.

McGehee, who has hit all five of his career homers in his last 13 games, returned to the dugout, covered his mouth and shouted into his helmet before tossing it aside. Then, he acknowledged a curtain call from the 39,872 fans at Miller Park who booed him coming off the field minutes before.

''Prince had to tell me to get out there and I didn't even know what he said. I didn't really know what was going on,'' McGehee said. ''If somebody would have told me this time last year I'd have 40,000 people calling me out of a dugout for a curtain call, I would've told you you were lying.''

That's because McGehee was in the Cubs organization, stuck at Triple-A Iowa behind slugger Aramis Ramirez before being placed on waivers in the offseason. The Brewers scooped him up because of his ability to play second, third and be an emergency catcher, and McGehee earned his way on the opening day roster with an impressive spring.

The Brewers tacked on three runs in the seventh and eighth innings to take a 10-3 lead, but the Mets forced the Brewers to use closer Trevor Hoffman with one out in the ninth after five straight hits.

Gary Sheffield , who had an RBI single in the seventh, hit a two-run homer in the ninth off reliever Carlos Villanueva to make it 10-6 moments after David Wright 's RBI double, and Villanueva allowed consecutive singles to Ryan Church and Martinez before being pulled for Hoffman.

The all-time saves leader forced Schneider to hit into a double play on his first pitch for his 18th save in 19 tries.

NOTES: Mets CF Carlos Beltran (right knee) was in Vail, Colo. getting a second opinion on his bone bruise from noted knee specialist Dr. Richard Steadman and will be re-evaluated later this week. ... Mets RF Ryan Church (ill) returned to the lineup and went 4-for-5.