SALT LAKE CITY -- One scenario played out in Bryant McIntosh's head during the hours he spent alone in the gym, honing his basketball skills.

The Northwestern guard's thoughts turned to March. He often envisioned racing down the court as the final seconds ticked away and hoisting up a game-winner.

McIntosh got to be a March hero for the Wildcats as he desired, but in a totally unexpected fashion. The junior scored 25 points and drained a pair of go-ahead free throws with 14.6 seconds left to help Northwestern hold on for a 68-66 victory over Vanderbilt in its first ever NCAA Tournament game on Thursday.

McIntosh did not anticipate being in that situation. The Commodores took a 66-65 lead on Riley LaChance's layup with 18 seconds left. But Matthew Fisher-Davis inexplicably grabbed McIntosh seconds later, sending the Wildcats guard to the free-throw line.

"When he grabbed me, I was kind of surprised," McIntosh said. "I had thought we were down one, instead of up one, so I was pushing the ball up the floor. And I thought maybe I made a mistake. To see we were down one and he fouled, I just had to put my mind on making the free throws at the end. Once I made them, it was just about getting a stop."

Vanderbilt still had a chance for a go-ahead basket, but LaChance missed a 3-pointer with six seconds remaining. It put a sour final note on the Commodores' rally from a 15-point, second-half deficit.

Fisher-Davis told ESPN's Michelle Steele, "I didn't know the score, to be honest. ... (I) saw Coach (Bryce) Drew point at my man, he was just telling me my matchup, and I got it confused with the foul. That was it."

On the other hand, Northwestern (24-11) felt nothing but jubilation in the wake of a dramatic finish. The eighth-seeded Wildcats will now face top-seeded Gonzaga in the second round of the West Region on Saturday.

"You dream of being in these games," Northwestern coach Chris Collins said. "That's why you get in the gym with these guys. That's why you put in the time.

"I tell these guys all the time, when you dream about these games, you don't dream about losing them. You don't dream about playing scared. You don't dream about being timid. You dream about being great, having confidence and winning."

Drew said that one mistake from Fisher-Davis didn't erase a strong game from the junior. Fisher-Davis scored 22 points to lead Vanderbilt and made many critical baskets to spark the team's comeback.

"You know, from day one, we teach our guys that we're a team," Drew said. "One play at the end or one or two plays at the end doesn't lose a game for us."

Scottie Lindsey and Dererk Pardon added 14 points apiece for Northwestern. For Vanderbilt, Luke Kornet scored 14 points, and LaChance chipped in 12.

McIntosh and Lindsey combined for jumpers over three consecutive possessions to spark a 10-0 run that gave Northwestern an early 14-5 lead. Vanderbilt went nearly 4 1/2 minutes without scoring until Fisher-Davis converted a three-point play to end the drought.

The Commodores cut it to a one-possession deficit behind 3-pointers from Payton Willis and LaChance. They twice drew with a point, first on a Fisher-Davis dunk and then when Kornet converted a three-point play to make it 25-24 with 4:02 left in the half.

The Wildcats were on top 34-27 at halftime.

Each time Vanderbilt tried to erase what remained of the deficit, the Wildcats countered with critical baskets and got stops on the other end. Northwestern held the Commodores without a basket over a nine-minute stretch spanning both halves before Joe Toye broke the ice with a tip-in basket.

It opened the door for the Wildcats to go on a run. Back-to-back jumpers from McIntosh gave them their first double-digit lead at 38-28 early in the second half.

"This is not a team you try to outscore," Collins said. "They're too prolific. They shoot it too well. They space you out. They get their 3-point game going."

Northwestern carved out its largest lead at 49-34 after scoring three unanswered baskets over a 90-second stretch. Gavin Skelly slashed to the rim for a layup and drew a foul, and then, after a missed free throw, Nathan Taphorn buried a second-chance 3-pointer to finish off the 7-0 run.

Vanderbilt didn't go away. The Commodores answered with a 12-0 run -- punctuated by back-to-back 3-pointers from Fisher-Davis -- to cut the deficit to 49-46. They finally took their first lead of the second half on a LaChance 3-pointer with 1:36 left, going ahead 62-61.

"It was the same as it has been all year: resiliency," Fisher-Davis said. "We started knocking down shots, getting stops, getting rebounds. We were feeling all good. We thought we were going to win that game."

NOTES: Northwestern shot 71.4 percent from the perimeter in the first half. G Scottie Lindsey and G Bryant McIntosh combined for 5-of-6 shooting from long-distance in the first 20 minutes, but they missed all four of their 3-point tries after the break. ... Vanderbilt was the first NCAA Tournament team to be awarded an at-large bid with 15 losses. ... Northwestern outrebounded Vanderbilt 37-30. ... The Commodores scored 27 bench points compared to 10 for the Wildcats. ... Northwestern became the fourth NCAA Tournament first-timer seeded eighth or better to win its debut game. The others were Seton Hall (1988), Florida (1987) and New Orleans (1987).