The senior guard scored 23 points and Providence won its first Big East tournament title since 1994 with a great defensive effort against McDermott and No. 14 Creighton in a 65-58 victory Saturday night.
The fourth-seeded Friars (23-11) used a 2-3 zone to hold the second-seeded Bluejays (26-7) 24 points below their season average and to an 8-for-30 effort from behind the 3-point line.
Cotton, who finished second to McDermott in the conference scoring but was also a unanimous first-team All-Big East selection, was the scoring star in the championship game and he was selected the tournament MVP.
''Unbelievable. He's been like that the whole year and he saved his best for last on one of the greatest stages ever,'' Providence coach Ed Cooley said of Cotton. ''He was fantastic.''
Cotton had a net draped around his neck and a smile on his face as he talked after the game.
''It's just a vindicating feeling to know that the Providence Friars are Big East champions,'' he said. ''This is something our school and our city hasn't seen in a long time. For us to finally bring that back home, it's top of the list.
''This has been years and years of blood, sweat, tears and praying.''
McDermott, who came in leading the nation in scoring with 26.5 average, finished 10 for 19 from the field, including 5 of 12 from 3-point range, for 27 points. He shined in his first two Big East tournament games, getting 35 in the quarterfinals against DePaul and 32 in the semifinal win over Xavier.
He had nine points at halftime as Providence held the Bluejays to a season-low 17 points in taking a nine-point lead.
''Got to give them credit. They're physical,'' McDermott said. ''But I think we handled ourselves pretty well all the way throughout league play on the physicality, and I think that's really going to help us going into the (NCAA) tournament.''
Providence was considered on the bubble coming into the game for an at-large bid to the NCAA tournament. That's a moot question now as the Friars won the Big East's automatic bid.
''We're just going to cherish this moment for the time being,'' Cotton said. ''We'll regroup when it's time.''
The Friars led by 12 points twice in the second half, the last time at 45-33 on a jumper by Kadeem Batts with 12:47 left.
The Bluejays got as close as 58-56 on McDermott's fifth and final 3 with 1:18 to play.
But the Friars held on from the free throw line, going 8 for 8 over the final 2:47 while scoring just one from the field.
''I really thought we were going to win that game. Things just felt right up there,'' McDermott said.
''Even when we had the big lead, I knew they were going to come up with a couple runs,'' he said. ''I've watched them all year and that's just the kind of team they are. And we've been through plenty of intense games throughout the whole season so I felt that that prepared us for a game like this.''
Providence had caused problems for Creighton before. The Friars held the Bluejays to 4 for 19 from 3-point range in an 81-68 victory in January. McDermott had it figured out in the rematch, scoring 45 points in his last home game just a week ago. The Friars took the advantage back Saturday night.
''We had to come up with something different than we did before,'' Cooley said of the zone.
McDermott came into the game shooting 45.6 percent from behind the arc and the Bluejays led the conference on 3s at 42.7 percent.
Creighton reached the title game in its first season in the Big East. The Bluejays, who didn't trail in the tournament until this game, won the last two Missouri Valley Conference titles before leaving. The loss ended Creighton's streak of winning 10 straight conference championship games. The last one it lost was to Tulsa in the 1984 Missouri Valley Conference title game.
''I think there's a whole city that didn't know much about Creighton that knows a lot about Creighton now,'' Bluejays coach Greg McDermott said.
The crowd of 15,290 at Madison Square Garden was charged from the start and a strong contingent of Creighton fans made the building shake as the Bluejays closed in on the Friars.
Cotton, who was 1 for 10 from the field and had 12 points in the quarterfinal win over St. John's and 18 points and 10 assists in the semifinal victory over Seton Hall, finished 8 for 18 from the field, including 3 for 9 from 3-point range. His biggest basket came on a drive under and around two defenders that gave Providence a 54-47 lead with 5:18 to go. That and LaDontae Henton's jumper with 45 seconds left were the Friars' only field goals in the final 9 minutes.
''I was scared to death of the fact that he didn't shoot it good the first two games because, in my mind, I'm saying, 'There's no way Bryce Cotton's having three bad games shooting the basketball in a row,' and that proved to be the case,'' Greg McDermott said.
Doug McDermott has 3,105 points, fifth on the all-time scoring list. He is trying to become the 11th player to be a three-time All-America and the first since Patrick Ewing of Georgetown and Wayman Tisdale of Oklahoma in 1985.
The trophy presentation was especially poignant for Providence which accepted the Dave Gavitt Trophy, named for the founder of the Big East and former Providence coach and athletic director.
''I hear ''Coach Gavitt'', and I say thank God for him,'' Cooley said. ''Thank God for his vision. Thank God for what he's done for basketball in general.''