SALT LAKE CITY -- Allonzo Trier didn't give up at halftime.

No one would have blamed Trier for not feeling like it was going to be his day. The Arizona guard missed all four shots he took in the first half and committed two costly turnovers. But he didn't back down.

Trier came out with renewed fire and energy after halftime and lifted the Arizona offense onto his shoulders. The sophomore scored all 14 of his points in the second half to fuel second-seeded Arizona's 69-60 victory over seventh-seeded Saint Mary's in the second round of the NCAA Tournament on Saturday.

Trier went 4 of 6 from the field in the second half and 5 of 6 from the free throw line.

"He regained his confidence," Wildcats coach Sean Miller said. "When he's confident offensively, our team is a lot better."

Freshman center Lauri Markkanen added 16 points and collected 10 rebounds to lead Arizona. It was Markkanen's sixth double-double of the season.

Dusan Ristic added 13 points and Kadeem Allen chipped in 12 for the Wildcats.

Arizona (32-4) advanced to the Sweet 16, where the Wildcats will play 11th-seeded Xavier. Miller coached the Musketeers from 2004 to 2009 before taking over in Tucson.

Jock Landale finished with 19 points and 11 rebounds and Calvin Hermanson added 14 points for the Gaels. Saint Mary's (29-5) has advanced to the Sweet 16 just one time during coach Randy Bennett's tenure.

The Gaels missed five straight shots in the final 1:25. Arizona, on the other hand, closed out the game making seven of its final 10 shots.

"It seemed like they started hitting some tough shots at the end," Hermanson said. "In the first half, I felt like we did a pretty good job on defense for the first like 10 to 14 minutes or so. We were forcing them to take tough shots and (it) seemed like they were only scoring when they got offensive rebounds."

Saint Mary's never trailed before halftime, but that quickly changed in the second half.

Trier scored seven straight points, highlighted by a go-ahead 3-pointer, to spark an 11-2 Arizona run. The sophomore then capped it off with a jumper to give the Wildcats a 55-48 lead with 6:57 remaining.

The Gaels pulled within 58-55 after Tanner Krebs buried a 3-pointer from the corner. Markkanen quickly answered with his own corner 3 on the other end to push Arizona's lead back to six.

Saint Mary's cut the Wildcats' lead to 65-60 with 1:54 left. The Gaels had a chance to get closer after Joe Rahon poked the ball away from Allen. A second 3-point shot attempt from Krebs drew iron.

Trier and Allen combined to make four free throws in the final 1:25 to seal the victory.

"We believe in the system we have and we believe in each other as players and we believe in our coach," Allen said. "We kept battling it out the whole game and we came out on top."

During the first half, Arizona faced similar problems knocking down shots that all Saint Mary's opponents endure at one point or another. The Wildcats went nearly eight minutes without scoring a field goal and missed eight straight shots during that stretch before Parker Jackson-Cartwright ended the drought with a 3-pointer.

It opened the door for the Gaels to carve out a double-digit lead. Landale scored on a putback layup and then turned a steal into a dunk to ignite a 12-4 run. Rahon and Emmett Naar polished off the run with back-to-back layups, giving Saint Mary's a 22-12 lead.

Markkanen hit five free throws during a 1 1/2-minute stretch to keep Arizona within striking distance. The Wildcats finally roared back to life after Jackson-Cartwright's 3-pointer and were able to cut the deficit to 30-29 going into the locker room.

Once Arizona heated up on offense, the Wildcats never cooled back down. They shot 59 percent from the field after halftime.

"It came down to that we didn't get enough stops," Rahon said. "We scored 30 in each half and I feel like we got great looks the whole game. We missed some 3s that we normally make that we have made all year."

NOTES: Three ties and nine lead changes occurred in the second half after Saint Mary's led for nearly 19 minutes before halftime. ... Arizona forced 13 turnovers and scored 15 points off of those turnovers. ... Saint Mary's shot just 23.8 percent (5 of 21) from 3-point range. .... The Wildcats have won four straight in the series with the Gaels dating to 1951.