Nelson earned his first career victory in his season debut Sunday, pitching 5 2-3 scoreless innings in a spot start to beat the Miami Marlins 7-1.
The Brewers gave Nelson a game ball and sent him back to Triple-A Nashville, which was the plan before the game.
''He was really impressive - dominant stuff,'' teammate Ryan Braun said. ''A guy who's that good, you know you'll see him again soon.''
Rated the Brewers' top prospect, Nelson was recalled to start for Yovani Gallardo, who is nursing a sore left ankle. Nelson allowed five hits and three walks, but Miami went 0 for 7 against the 6-foot-5 right-hander with runners in scoring position.
''He's got really good stuff,'' manager Ron Roenicke said. ''He let a lot of balls get away from him, but he made some great pitches when he needed to and threw some great sliders. With him it's just going to be a matter of trying to command the ball, and not let so many balls get up and away from him.''
It helped the rookie that he had a 5-0 lead before taking the mound in the second inning. Braun led the way with four hits, including a double and a triple. The Brewers' slugger, who has been nursing a sore right side, came into the game 5 for 27 on their trip.
Miami's Randy Wolf (0-1) made his first start since September 2012 and was treated harshly. The 37-year-old left-hander, who is trying to come back from the second Tommy John surgery of his career, gave up nine hits and six runs - four earned - in five innings.
''This is not the first time I've had a bad game,'' Wolf said. ''The only thing I can take out of this game is that things got better as the game went on.''
Wolf was filling in for ace Jose Fernandez, sidelined earlier this month by a season-ending elbow injury.
NL Central leader Milwaukee won two of three games in the series and improved to 18-6 against the Marlins since the start of 2011.
The Brewers went 4-6 on their longest trip of the season. Miami fell to 20-8 at Marlins Park, still the best home record in the majors.
''I think it was a classic case of being effectively wild,'' the Marlins' Casey McGehee said. ''It was kind of a weird outing. He was giving the appearance that he was all over the place, but then when he was in the zone he wasn't in the fat part of the plate. His stuff was certainly there. There's a lot to like about the kid.''
Nelson twice struck out Stanton, the major-league RBI leader. But the rookie wasn't too impressed with himself.
''I battled myself mechanically all day,'' Nelson said. ''I didn't have my best stuff. But you're not going to be at your best every time out. This is good experience. You remember the good and the bad, build off that and build confidence, and hopefully next time up get deeper into games.''
Gallardo is scheduled to rejoin the rotation and start Wednesday against Baltimore. Before Nelson's season debut, the Brewers were the only NL team to use just five starting pitchers this season, and he'll return to standby status.
''We like our guys,'' Roenicke said, ''but if something happens with an injury, we feel really good about bringing him back.''
Notes: INF Irving Falu will be recalled from Nashville to take Nelson's roster spot. ... The Marlins had two infield hits to increase their season total to 59, most in the majors. ... Miami will begin a three-game series Monday at Washington, with RHP Nathan Eovaldi (3-2, 3.41) scheduled to start against RHP Tanner Roark (3-2, 3.42). ... The Brewers return home to begin a three-game series Monday against Baltimore, with RHP Kyle Lohse (6-1, 2.67) scheduled to face RHP Chris Tillman (4-2, 4.21).