AUBURN HILLS, Mich. -- Memphis' defense gave St. Mary's fits all afternoon but the Tigers still had to sweat it out until the final buzzer.
Joe Jackson had 14 points, seven assists and six rebounds as sixth-seeded Memphis barely won its NCAA Tournament opener 54-52 over St. Mary's in the Midwest Region at The Palace on Thursday.
St. Mary's Matthew Dellavedova missed a 3-pointer at the buzzer after a Jackson turnover with 1.9 seconds left.
"We missed some free throws at the end but all I know is we got the win," Memphis coach Josh Pastner said. "This is tournament time and it's just about surviving and advancing. We got the win, a great win, and defensively I thought we were awesome."
Memphis' defense keyed the victory, as it made 12 blocks, including eight by D.J. Stephens, and nine steals.
"It was pretty tough. He's a pretty big guy," St Mary's Brad Waldow said. "Coming from the weak side, you can't see the guy coming and he's really athletic."
Tarik Black supplied 12 points and seven rebounds and Adonis Thomas added 12 points for the Tigers, who led by 15 in the first half and hung on the rest of the way.
Dellavedova, an 86 percent free throw shooter, missed two from the line in the final minutes, including the front end of a 1-and-1 with 4:16 left.
Memphis (31-4), which went undefeated in Conference USA and has gone 25-1 since losing to Louisville on Dec. 15, advanced to play No. 3 seed Michigan State in the third round on Saturday. The Spartans defeated Valparaiso in the first game of the day.
Waldow scored 17 points for Saint Mary's (28-7), which had a quick turnaround after defeating Middle Tennessee in the first round on Tuesday night. Its top player, senior Dellavedova was held to 10 points and he also missed two key free throws in the second half. The 11th-seeded Gaels, who were averaging 7.9 3-pointers per game, shot 3-for-15 from long range.
"No way is Matt going to score when he's got two guys guarding him and then they denied him the catch when he tried to get it back," St. Mary's coach Randy Bennett said. "For him to do what he did was remarkable. Wish he would have hit that last shot and so does he. But Matt wasn't the problem at all. He was the solution. Matt was why we had a chance at the end."
Clinging to a three-point advantage midway through the second half, the Tigers went on an 8-2 run to push the lead to 44-35. Stephens had a dunk and Chris Crawford, who averaged 25.7 points in the Conference USA tournament, made a 3-pointer for his first points of the game.
The Gaels pulled within four before Jackson made a three from the top of the key. St. Mary's never got closer than four until the closing seconds. Eividas Petrulis banked in a 3-pointer to make it a two-point game and Jackson then lost the ball after the inbounds but Dellavedova misfired after a timeout.
"They turned up the defensive intensity, so we just had to continue to fight," Jackson said. "We were up 10 but everybody knows that's not anything in the NCAA Tournament. We just had to show our maturity and put it away."
Jackson had 10 points and five assists by halftime as Memphis led 32-22. Jackson piled up eight points and three assists during a 19-2 run that gave the Tigers a 28-13 advantage. Black scored the last six points of the outburst.
Dellavedova was held to six points on 2-for-8 shooting and made four turnovers before halftime.
NOTES: The Tigers were the only other team besides Gonzaga to enter the tournament with 30 wins. ... Memphis had a 7-3 record as a No. 6 seed in previous NCAA Tournaments. ... The Gaels made the Sweet 16 in 2010 but lost their NCAA Tournament opener to Purdue last season. ... St. Mary's hadn't lost to anyone except Gonzaga since Northern Iowa defeated the Gaels 82-75 on Dec. 22.