TULSA, Okla. -- USC wouldn't go away and finally pulled off the upset of SMU.

The 11th-seeded Trojans erased multiple double-digit deficits on their way to a 66-65 victory over sixth-seeded SMU in the East Region on Friday at the BOK Center.

Trojans guard Elijah Stewart hit a 3-pointer from the right corner with 37 seconds left that ultimately felled the Mustangs.

"We ran the play previously before, and I was open," Stewart said. "We ran the same play again, and I was open, and I just let muscle memory take place."

SMU guard Shake Milton took a running jumper in the lane with one second left, but it bounced away off the rim as the buzzer sounded.

Stewart said he sensed some confusion between the Mustangs players at the end and the Trojans guard just hoped for the best.

"I noticed that two players were arguing about who was going to take the last shot," Stewart said. "Usually when something like that happens, like whoever shoots it, it just messes with you. The floater was short, and I felt like it could have went either way, honestly. I just had my eyes closed."

Stewart led USC (26-9) with 22 points while forwards Chimezie Metu and Bennie Boatwright each added 14.

Forward Semi Ojeleye scored 24 points to lead SMU (30-5), guard Sterling Brown added 17 and Milton had 11.

USC employed a 2-3 zone defense for the final 13 minutes that helped the Trojans climb out of a nine-point hole in the second half.

The Mustangs led 50-41 with 13:28 left, but they managed just 15 points in the final 12 minutes.

"They've got great size," SMU coach Tim Jankovich said. "That's one of the real factors in how good your zone is, and they are very big, very, very big, and they're very athletic. I thought it was the most active they've played it in any of the games that we watched. So give them credit for that."

Boatwright nailed a 3-pointer from the top of the arc that gave USC its first lead of the contest, 63-62, with 2:09 left. But Milton, who had a pair of key 3-pointers late in the game, answered with a trey that put the Mustangs back in front.

That set up Stewart's game-winner to complete a resilient effort for the Trojans, who advance to play No. 3 seed Baylor in the second round on Sunday.

USC continued a trend of teams that win a play-in game earlier in the week having success in the first round. Since the field was expanded to 68 teams in 2011, teams that are seeded No. 13 or higher that win a play-in game are now 7-5 after the Trojans' victory.

After a whirlwind few days, USC now has a relatively normal period to get ready for third-seeded Baylor.

"You prepare your entire life for these moments, and you have to step up, and our guys stepped up in the moment tonight and won a big game," USC coach Andy Enfield said. "And now take a deep breath and enjoy the moment because it's most important to enjoy what you have."

SMU saw its 16-game winning streak snapped and failed in its attempt to notch its first NCAA Tournament victory since 1988.

"Amazingly disappointed," Jankovich said about his emotions after the loss. "This was a team that I love dearly and I feel very badly for the way they're feeling right now."

USC opened the second half with a 10-2 surge to erase SMU's 38-30 halftime lead.

Metu threw down a dunk to tie it at 40 with 15:39 left. But SMU stopped the run on the other end when Ojeleye got inside for a layup and completed a three-point play.

SMU extended a double-digit lead in the first half when Ojeleye got to the basket for a layup, capping a 14-3 run that gave the Mustangs a 30-18 lead with 7:31 left in the first half.

USC punched back with a 10-2 run and cut SMU's lead to four when Stewart made a layup. But the Mustangs still led by eight at the break after holding USC to 39 percent shooting and outrebounding the Trojans 19-14 in the first half.

Ojeleye led SMU with 11 points and seven rebounds in the first 20 minutes. Stewart scored 11 in the first half to pace USC.

NOTES: USC defeated SMU earlier this season, winning 78-73 on Nov. 25 in Los Angeles. The Trojans lead their all-time series versus SMU, 5-1. ... The Mustangs' three games versus ranked opponents this season were all against the same team -- Cincinnati. SMU defeated the Bearcats in the AAC tournament championship game and on Feb. 25 in Dallas, and lost on Jan. 12 in Cincinnati. ... USC coach Andy Enfield is now 4-2 in the NCAA Tournament after the Trojans lost in the first round last season. Enfield led Florida Gulf Coast to the Sweet 16 in his first NCAA Tournament appearance as a coach in 2013.