Joe Jackson scored 18 points, Shaq Goodwin had 17 and the 21st-ranked Tigers advanced to the semifinals of the Old Spice Classic by beating Siena 87-60 on Thursday night.
Michael Dixon Jr. added 16 points for Memphis (3-1).
"Very happy for the win," coach Josh Pastner said. "We don't take wins for granted. I thought we played hard. Thought we did some good things."
The Tigers' lone loss this season came against No. 5 Oklahoma State, a game the Cowboys won handily 101-80 on Nov. 19. Memphis could get a rematch in the championship game of this event Sunday if both teams win Friday.
Siena (2-5) got 11 points from Brett Bisping. Leading scorer Rob Poole (15.5 points per game) was held to six on 3-of-15 shooting.
"I expected us to compete a little harder than that," Siena coach Jimmy Patsos said. "I thought there were spurts we competed. They're a more talented team than us.
"I had some guys wake up and realize you have to play at a high, high level. And you have to execute to win. We're trying to win the MAAC in March, and I saw a lot of bad habits that I'm responsible for as the head coach and I will do my best to break."
After a slow start, Memphis grabbed a 48-31 halftime advantage as Goodwin and Dixon both scored 13 points. Jackson added 12, including a 3-pointer just before the buzzer.
Lavon Long's layup got Siena to 52-41 just 3 minutes into the second half.
Jackson had a three-point play to give the Tigers a 59-41 lead with 15 minutes to go. Dixon extended the advantage to 71-47 on a 3-pointer.
"My teammates just found me in some spots," Dixon said.
Siena held two-point leads four times early on, including 8-6 when Bisping scored on a layup.
Memphis took its first lead, 10-8, on Goodwin's dunk 5 minutes into the game.
"The biggest thing is, he's playing above the rim, not at the rim," Pastner said.
Jackson's first points, on a layup midway through the half, made it 18-12.
The Tigers went ahead 32-18 when Dixon connected on his second long-range jumper 6 minutes before the break.
Poole missed his first seven shots before making a layup late in the first half.