Trahson Burrell had 15 points, while Avery Woodson had 12 to give the Tigers (2-2) a split of two games in Las Vegas.
Brenton Scott led Indiana State (3-3) with 12 points and Khristian Smith added 10 as the Sycamores shot 33 from the field.
After the Sycamores scored the game's first six points and later led 17-11. The Tigers responded with a 14-0 run. Within the run, Memphis took the lead for good at 20-17 with 7:13 left.
Memphis turned that surge into a 29-5 run to end the first half with a 40-22 lead and eventually built a 22-point advantage five minutes into the second half.
The Sycamores cut that lead to seven twice with less than two minutes left.