"I'm part of that. I popped out. I'm guilty of that," Lucroy said. "We let him off the hook. You have to take advantage of the situations, and when you don't that's when you get beat like that."
Nieuwenhuis accounted for another run in the sixth when he walked, stole second, took third on a wild pitch and scored on John Buck's single. He doubled in the eighth and scored on Juan Lagares' single to make it 9-4.
Nieuwenhuis tripled in another run in the Mets' three-run ninth.
Francisco opened the fourth with his 11th home run to trim it to 7-3. The Brewers scored single runs in the seventh and eighth on RBI doubles by Gomez and Logan Schafer.
Hellweg's wildness helped the Mets score twice in the first. Young singled to open the game and moved to third on Wright's one-out single to right. Hellweg then issued consecutive walks to Davis, who entered hitting .161, and Nieuwenhuis to force in a run. Wright scored on Lagares' fielder's choice.
Milwaukee answered with two unearned runs in the bottom of the inning on an RBI double by Gomez and a sacrifice fly by Ramirez.
It was the second consecutive rough start for Hellweg, who was rocked for seven runs in 1 2-3 innings in his first major league start on June 28. He had gone 6-0 with a 1.64 ERA in his last seven starts at Triple A Nashville before being called up by the Brewers.
"The potential he has is the stuff that he has," Roenicke said. "He has a great fastball, a real good moving fastball. He's got a nice breaking ball. But he has to command those pitches. Unless you can command them in the big leagues, you're not going to do well."
NOTES: Brewers outfielder Ryan Braun, on the disabled list with an injured right thumb, took swings in the indoor cage Friday. "I haven't talked to him since he swung. I talked to (third base coach) Ed Sedar and he said he swung the bat real well. I just haven't asked Ryan how the hand felt," Roenicke said. Braun is scheduled to take batting practice on the field Saturday and Monday. When Braun is ready to be activated, he won't be sent on a rehab assignment, Roenicke said. ... Wheeler's two-out single to right in the third was his first major league hit. . Josh Edgin pitched the final 1 1-3 innings for his first save in two opportunities.