If Friday night's sweep of Radford was the warm-up, then Saturday's second-round match against Colorado was the wake-up call for No. 10 Minnesota.

Tori Dixon and Ashley ­Wittman each had 19 kills, and the Gophers (29-6) edged the Buffaloes (18-14) 3-2 to advance past the Round of 32 in the NCAA Tournament for the fifth straight year.

Mission accomplished for Minnesota, but it didn't come easily.

A night after never truly being challenged by Radford, Minnesota had its hands full with a Colorado team that ­finished seventh in the Pac-12 this fall.

"We weren't expecting any of these matches to be easy, and especially not tonight," Gopher head coach Hugh McCutcheon said. "Colorado is a good volleyball team. … For us to think that it was going to be a sweep or somehow it will be easy is naive."

In the end, the Gophers did just enough to move on. And, when they needed big plays, their heavy-armed stars, ­Wittman and Dixon, came up big in their final match at the U's Sports Pavilion.

Leading 8-4 in the fifth, ­Wittman finished off a long rally kept alive by a diving dig by sophomore Daly Santana to push the Gophers to a five-point lead. Dixon then clubbed each of the last three points to close out the final set 15-9.

"It's been a privilege to play in front of all these fans, and it's been a great four years," ­Wittman said. "Going out with a win in the NCAA Tournament, it's awesome and I can't wait to go on and play in the Sweet 16."

The Gophers are now 18-1 all time in the second round of the tournament. They play Stanford in the Sweet 16 at the Lexington (Ky.) Regional on Friday.

On paper, that outcome seemed all but assured before the match's opening serve Saturday. But the Buffaloes, who beat then-No. 1 Washington earlier this season, had an upset in mind.

And the Gophers came out flat.

Minnesota made just enough good plays to take the opening two sets 25-20 and 25-18 — but had just enough mistakes, to make it feel like the Buffaloes had the ­momentum.

From the get-go in the third, the errors finally caught up with the Gophers. The Buffaloes jumped out to a 7-1 lead and cruised to a 25-17 win.

The fourth didn't get much better. Minnesota fell behind early once again, but kept close pace throughout. The Gophers repeatedly fought back to within a single point, but, each time, Colorado would pull away again. The Buffaloes took the set 25-21.

Finally, the Gophers took control in the fifth.

"Our athletes responded appropriately and were at their best when their best was needed," McCutcheon said.