Milwaukee snapped a 2-2 tie with a run in the seventh off reliever David Weathers (1-1). John Vander Wal and Wes Helms started the inning with singles and Eddie Perez sacrificed them into scoring position.
Clayton was intentionally walked to load the bases and pinch-hitter Brady Clark, a former Met, delivered a sacrifice fly to center off Mike Stanton. Timo Perez made the catch in center, but his throw reached catcher Mike Piazza on three bounces as Vander Wal slid across the plate.
The Mets, who were 29-9 against the Brewers, squandered golden opportunities in the eighth and ninth innings. Luis Vizcaino walked Roberto Alomar to start the eighth and Roger Cedeno followed with a single. But Piazza grounded into a double play and Vizcaino struck out Cliff Floyd to strand Alomar at third base.
In the ninth, Ty Wigginton and Perez singled off DeJean with one out. Rey Sanchez followed with a grounder to shortstop, but the ball bounced off Clayton's chest. Clayton quickly retrieved it and fired to first, but Sanchez beat the throw.
DeJean did not let the miscue affect him. He threw a first-pitch strike to Gonzalez. On the second pitch, Gonzalez hit a grounder to third baseman Helms, who threw to catcher Perez for the forceout. Perez fired to first to complete the double play.
It was the fifth save in six chances for DeJean. John Foster (2-0) pitched a hitless inning for the win.