Zack Wheeler of the Mets pitches to a Milwaukee Brewers...

Zack Wheeler of the Mets pitches to a Milwaukee Brewers batter during the first inning at Miller Park. (July 5, 2013) Credit: Getty Images

The Mets hadn't finished batting practice yet when Zack Wheeler emerged from the dugout. Wearing baggy shorts and a loose-fitting hooded sweatshirt, the highly touted pitching prospect could have been mistaken for a boxer waiting anxiously for the bell to ring.

But once it came time to take the mound Friday night, Wheeler struggled to consistently command his impressive arsenal. Though he put himself in position to get the win in a 12-5 rout of the Brewers, he hardly scored a knockout.

Wheeler did what he had been told to, pumping fastball after fastball into the mitt of catcher John Buck. He emerged from Round 4 of his young big-league career having allowed three runs -- though only one earned -- in five innings. He gave up seven hits and walked as many as he struck out, three. Of his 98 pitches, he threw only 56 for strikes, and he allowed a long solo homer to Juan Francisco.

"A hundred pitches in five innings is a lot," Mets manager Terry Collins said.

But it was good enough on a night when the Brewers aided the Mets with three errors and four unearned runs.

Kirk Nieuwenhuis went 4-for-4 with two walks, a double, a triple and a career-high five RBIs. He reached base in all six plate appearances. Ike Davis was 3-for-5 with a strikeout, a walk and a pair of RBIs in his first game back from a demotion to Triple-A Las Vegas that lasted nearly a month.

Wheeler again flashed the electric stuff that has made him so highly valued and highly scrutinized. His fastball sat in the mid-90s, more than good enough to tame the Brewers.

"I'm happy with my outing, even though there were low points," Wheeler said.

Wheeler allowed a pair of unearned runs in the first inning, when Daniel Murphy lost the handle on a double-play ball, the Brewers scored on a double and a sacrifice fly and the Mets nailed a runner at the plate.

In the third, Wheeler dodged trouble, partly because of Norichika Aoki's unsuccessful attempt to take home on a double steal.

In the fourth, Wheeler made perhaps his most obvious mistake, grooving a 96-mph fastball. Francisco unloaded, sending a towering drive into the batter's eye in center.

In the first, Brewers pitching prospect Johnny Hellweg walked Nieuwenhuis with the bases loaded to force in the first run. The Mets made it 2-0 when Jean Segura sailed a throw to first base, allowing David Wright to score.

In the second, Segura misplayed a grounder and Hellweg threw to the wrong base after fielding a comebacker. The gaffes opened the door for the Mets to score three unearned runs.

Nieuwenhuis delivered the big hit, a two-run single that bounced just beyond the reach of second baseman Rickie Weeks. That gave the Mets a 5-2 lead.

In the fourth, third baseman Aramis Ramirez botched John Buck's grounder to give the Mets their second run of the inning and a comfortable 7-2 cushion.

Wheeler allowed the solo shot to Francisco in the fourth but walked away unscathed from a bases-loaded jam in the fifth. After a walk to Ramirez that loaded the bases, Wheeler got Jonathan Lucroy to fly out before freezing Francisco on a slider.

Said Wheeler: "Command will come once I start settling down a little bit."