SALT LAKE CITY -- Playing under a spotlight is nothing new to Gonzaga this season.

The Bulldogs felt scrutiny all season as they climbed to the top ranking in the country and ripped off 29 straight wins before losing in their regular season finale to BYU. Weathering a second-half rally from an inspired underdog such as Northwestern wasn't going to be enough to knock them off their feet.

Gonzaga survived the rally and claimed a 79-73 victory over the Wildcats in the second round of the NCAA Tournament on Saturday. The Bulldogs faced the pressure and won -- like they have done all season long.

"We don't think of anything as pressure," Gonzaga's Nigel Williams-Goss said. "We were under pressure all year long. We were undefeated and we didn't feel any of that. This is what we live for, we prepare for and we enjoy doing. We all enjoy competing at the highest level."

Williams-Goss scored 20 points while Jordan Mathews and Zach Collins added 14 apiece to help No. 1 seed Gonzaga advance to the Sweet 16 for the third consecutive season. The Bulldogs (34-1) prevailed despite scoring just four baskets over the final 13 minutes of the second half.

One of the game's most intense moments came late in the second half during a Northwestern surge. Collins committed what should have been called a goaltending violation after blocking Dererk Pardon's layup attempt with 4:58 left. Collins reached through the basket from below and blocked the shot that would have cut the deficit to three.

Wildcats coach Chris Collins got hit with a technical foul for protesting the no-call and Williams-Goss made a pair of free throws on the other end. The NCAA released a statement following the game that confirmed the officiating crew erred in not calling goaltending.

"It should have been a three-point game," Chris Collins said. "The way we fought was great and we fought to the very end. We just came up a little bit short."

Bryant McIntosh scored 20 points and Vic Law added 18 and eight rebounds to lead the Wildcats. Northwestern (24-12) rallied from a 21-point deficit in the second half, but ultimately couldn't fully overcome a sluggish start on offense.

Northwestern players are headed home with a disappointing loss, but also a feeling that they have just scratched the surface.

"We know we're a good team," Law said. "We had all the pieces to be special. I feel like this is just a building block. This is just a beginning and I can't wait to see what the future holds."

Northwestern could not get anything cooking on offense before halftime. The Wildcats shot just 30 percent from the field and did not make a 3-pointer until Law buried a long-distance basket with 1:01 left in the half.

Things changed once those outside shots started falling in the second half. Nathan Taphorn buried a pair of 3-pointers to cap a 15-4 run for Northwestern and cut Gonzaga's lead to 59-50.

Once the Bulldogs' lead fell under single digits, the Wildcats ratcheted up the pressure. They trimmed the deficit further to 63-58 with 5:31 remaining on Law's putback dunk following a missed 3 from McIntosh.

Gonzaga eventually extended its lead to 69-59 on a Collins' jumper with 3:00 left. The Wildcats never drew closer than five points the rest of the way.

Even though the blown call on Collins' goaltending resulted in a pivotal four-point swing, Bulldogs coach Mark Few wasn't convinced that was the ultimate difference maker.

"I get it was a big play," Few said. "But there were other big plays. I thought we responded several different times to their runs throughout the second half. I wouldn't put it all on this technical."

Gonzaga took full advantage of Northwestern's early offensive struggles.

The Bulldogs allowed only a single basket over a 10:15 stretch in the first half and built a 22-8 lead during that timeframe. Williams-Goss and Mathews made back-to-back baskets to break an early 6-6 tie. Williams-Goss finished off the lengthy run on a dunk with 6:27 left before halftime.

The Bulldogs went up 34-12 with 2:30 remaining before halftime when Przemek Karnowski scored a pair of baskets sandwiched around a dunk from Williams-Goss over three straight possessions.

Gonzaga stifled Northwestern's offense early by rotating players on and off the ball. It kept the Wildcats from getting dialed in on the perimeter.

Northwestern cut the deficit to 44-32 early in the second half on Law's corner 3. Williams-Goss quickly dialed up a basket from the perimeter on the other end. Collins followed by driving to the rim and converting 3-point plays on back-to-back possessions to give Gonzaga a 53-34 lead.

The Wildcats didn't go away and charged back enough to make the Bulldogs feel uncomfortable down the stretch.

NOTES: Northwestern went just 1 of 11 from 3-point range in the first half. The Wildcats missed 10 straight baskets from the perimeter before finally making one. ... Gonzaga C Zach Collins finished with four blocks. ... Northwestern outscored Gonzaga 17-3 in points off turnovers after halftime. The Wildcats forced 11 second-half turnovers. Gonzaga G Nigel Williams-Goss scored 14 of his 20 points in the first half.