Max Muncy got the night rolling for the RockHounds, then put the finishing touches on it.
The Athletics' No. 15 prospect homered and drove in a career-high six runs on Tuesday night, leading a 23-hit attack as Double-A Midland rolled to a 20-8 victory over visiting Northwest Arkansas.
Muncy opened the scoring in the bottom of the first inning by drawing a bases-loaded walk in the bottom of the first inning. He added a two-run single in the fifth and capped the scoring with a three-run homer in the eighth.
The 23-year-old designated hitter surpassed his previous high of five RBIs, established on a three-homer night for Class A Advanced Stockton last June 5. Muncy had gotten off to a slow start in the power category this season, entering Tuesday's game with one extra-base hit and one RBI.
A 2012 fifth-round pick, Muncy had a big year in 2013, slugging 25 homers while plating 100 runs in 140 games between Stockton and Midland.
Josh Whitaker collected four hits, including his second homer of the season, and four RBIs, while Dusty Coleman drew three of the RockHounds' eight walks and scored four times.
A's No. 9 prospect Billy Burns chipped in two hits and provided the highlight of the night when he scored from second base on D'Arby Myers' sacrifice fly in the second inning.
Jorge Bonifacio, the Royals' No. 4 prospect, slugged a grand slam for the Naturals.
Midland starter Drew Granier bounced back from a rough season debut but did not figure in the decision. He gave up a run on six hits while striking out three over four innings. Nate Long (1-0) was credited with the win, despite yielding a run on two hits over two frames.
Jason Adam (0-1), Kansas City's ninth-ranked prospect, took the loss in his first start of the year. The 22-year-old right-hander surrendered eight runs -- six earned -- on seven hits over three innings.