Karl-Anthony Towns scored 19 points, Mike Conley added 18, Naz Reid 17 and Rudy Gobert 16 as the Timberwolves spoiled the home debut of new Bucks coach Doc Rivers, whose No. 31 Marquette jersey hangs from the Fiserv Forum rafters.
Rivers opened his Milwaukee coaching tenure with a five-game trip during which the Bucks went 1-4.
The Bucks were operating at far less than full strength.
Damian Lillard missed a second straight game and Khris Middleton also was out because of their sprained ankles, though Brook Lopez returned after missing three games as his wife gave birth to their child.