The Sycamores (9-2) matched the won-loss record of the 1979-80 team to open the season and haven't had a better start since the 1978-79 team opened 10-0.
Indiana State closed the first half on a 9-3 run to go ahead 22-15, then built the lead to as many as 20 points when Myles Walker capped a 13-2 run with a jumper that put the Sycamores on top 42-22 lead with 5:29 remaining.
Steven McClellan had eight points to lead Louisiana-Monroe (1-12), which has lost six straight.
The win capped a season sweep of the non-conference series for the Sycamores, who also beat Louisiana-Monroe 71-59 on Nov. 14.
Maryland point guard Melo Trimble, considered a lock to leave the program before struggling in the second half last season, has withdrawn from the NBA draft and will return for his junior season.
Louisville's Chinanu Onuaku, who recently underwent a medical procedure to correct a heart rhythm issue detected during the combine, will keep his name in the NBA draft pool.
Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.