Tiby was 3 for 4 from 3-point range and went 4 for 4 from the free-throw line. Teammate JeVon Lyle added 16 points, Steve McWhorter chipped in 15 and Akeem Spring finished with 12.
The Panthers (5-6) took a 20-point lead after Lyle hit a 3 with 11:56 left on the clock. Jordan Gregory responded with 14-straight Montana points, bringing the Grizzlies within 12, 63-51, with 4:08 left. Springs scored six points in the final two minutes to keep Milwaukee ahead.
The Panthers shot 56 percent in the opening half with Tiby and Lyle chipping in nine points apiece. Montana was 0 for 6 from 3-point range at the break.
Gregory finished with 21 points, 17 of those coming in the second half for the Grizzlies (3-6).