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SALT LAKE CITY -- Thriving in high-pressure situations has turned from a weakness into a strength for Northwestern this season.

That could come in handy Saturday, when the eighth-seeded Wildcats challenge the top-seeded Gonzaga Bulldogs in a second-round West Region game.

The Wildcats (24-11) became just the fourth team seeded eighth or lower to win in their NCAA Tournament debut when they edged Vanderbilt 68-66 on Thursday. Bryant McIntosh clinched the victory with a pair of go-ahead free throws with 14.6 seconds left after the Commodores rallied from a 15-point deficit.

Vanderbilt took its first lead of the second half when Riley LaChance drilled a 3-pointer to put his team ahead 62-61 with 1:36 left. The two teams traded baskets until McIntosh scored his free throws. Never at any point did Northwestern wilt under pressure, and it offered a beautiful example to Wildcats coach Chris Collins of how far this group of players has progressed.

"It's been our whole process over the past couple of years finding a way and so many times in the past couple of years getting our hearts broken, not being tough enough to finish games," Collins said. "And this year we've lost a few. But, for the most part, I felt really good how we've handled end-of-game situations in close games. We've executed well. We've gotten stops. We've made free throws."

Northwestern used an efficient offense to prevail in the end. The Wildcats shot 49.1 percent from the field and scored 32 points in the paint. It helped them build a 49-34 lead at one point, giving the team a big enough cushion to weather Vanderbilt's rally.

Now a much bigger challenge awaits with top-seeded Gonzaga.

The Bulldogs (33-1) won their opening game for the ninth consecutive season, pulling away in the second half to beat 16 seed South Dakota State 66-46.

For a half, the Jackrabbits had Gonzaga on the ropes. The Bulldogs didn't take their first lead until Zach Collins scored a layup 1:40 before halftime. It was part of a 7-0 run that gave Gonzaga a 26-22 lead. The Bulldogs never trailed after halftime.

"We were able to grind out a tough game, not a pretty game," Gonzaga guard Nigel Williams-Goss said. "It feels good when you win a game when you know you didn't play your best."

Defense and rebounding helped Gonzaga put away the pesky Jackrabbits. The Bulldogs finished with a 50-38 advantage on the boards and held South Dakota State to just three points over a decisive nine-minute stretch in the second half that crushed the Jackrabbits' upset hopes.

Gonzaga isn't likely to experience the same degree of offensive struggles in the second round. The Bulldogs are a team accustomed to scoring early and often. As long as the defense is there, Gonzaga is confident the offense will always fall into place like it did against South Dakota State.

"We knew on the defensive end we were doing our jobs and, eventually, the shots were going to fall," Zach Collins said. "We put in the work, hours upon hours in the gym, and we're all confident shooters and post players. We weren't worried about it. We knew if we kept getting the looks we wanted to, they would eventually fall."

Gonzaga has advanced out of the second round each of the last two seasons since falling to 9 seed Wichita State as a 1 seed in the 2013 NCAA Tournament.