The Royals managed only two hits off Estrada, who retired his last 10 batters. Estrada finished the spring by pitching 17 consecutive shutout innings.
Lucroy, who struggled at the plate this spring, connected off hard-throwing starter Yordano Ventura with two outs in the third.
Aramis Ramirez singled, doubled and drove in a run for the Brewers. Logan Schafer had three hits and two RBIs. Minor leaguer Michael Ratterree hit a solo home run in the seventh.
Kansas City scored two ninth-inning runs off reliever Francisco Rodriguez.
The Brewers finished the spring 13-18, while the Royals went 12-16-2.