Antonio Barton's 3-point play with 8:12 remaining put Memphis ahead for good at 46-45 and Jackson's trey with 4:28 left gave the Tigers a six-point lead at 58-52.
Charles Carmouche added 12 points for the Tigers (9-1).
The Islanders (4-7) were led by Hollis Hill with 16 points. Justin Reynolds and Terence Jones each added 11 in the loss.
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