The Bucks looked to be in control, up 77-67 on the Indiana Pacers after three quarters, before former Marquette star Travis Diener took over in the fourth quarter and led the Pacers to a 105-97 win in Indianapolis.
Diener scored 15 of his 18 points in the fourth quarter, hitting 5 of his 6 three-pointers in the final quarter. Danny Granger had 27 points to lead all scorers for the Pacers.
Michael Redd had 24 for the Bucks. Charlie Villanueva added 22 points and 13 rebounds.
The Bucks return to action Tuesday night at home against Boston. It's one of six games left in the NBA regular season for Milwaukee.