KANSAS CITY, Mo. — Adalberto Mondesi’s walk-off RBI single in the bottom of the 10th inning drove in the winning run in the Kansas City Royals’ 1-0 win over the Cleveland Guardians in front of an announced 17,103 at Kauffman Stadium on Saturday afternoon. Rookie third baseman Bobby Witt Jr. made an outstanding defensive play from a knee and threw out a runner at the plate in the top half of the 10th to keep the game scoreless. Royals starting pitcher Brad Keller turned in a stellar performance in a pitcher’s duel between him and Guardians starter Zach Plesac. Keller allowed just two hits and w…