SAN ANTONIO -- Saturday's Final Four matchup between Duke and Houston seemed like another stop on the Blue Devils' march to a national championship, just another prelude to the looming Cooper Flagg and Duke coronation.

After Tyrese Proctor's free throw put Duke up by 14 points with 8:17 left in the second half, the inevitable seemed closer than ever. That was cemented when Flagg buried a 3 to extend the Blue Devils' lead to nine with three minutes remaining.

Except Houston's culture doesn't allow concessions.

"It ain't over because they still got time on the clock," Cougars guard L.J. Cryer said after the game.

Houston went on a 9-0 run in the final 35 seconds to win 70-67, shocking Duke and the Alamodome crowd to advance to Monday's national championship game against Florida.

Cryer led the way with 26 points and six 3-pointers, while Flagg had 27 points, 7 rebounds and 4 assists in what will likely be his final college game. The Cougars, who advanced to the title game in 1983 and 1984, can win their first national championship.

Saturday night was a combination of a stunning Duke collapse and desperate Houston comeback.

After Proctor's free throw, Houston responded with a 10-0 run to shift the momentum. But Duke pushed the lead back to nine with 3:03 left on Flagg's corner 3-pointer. The Blue Devils didn't make another shot from the field.

"Houston is a team that doesn't quit," Duke coach Jon Scheyer said. "I mean, they're never going to stop. So my messaging throughout the whole way with the team was, understand this team doesn't go away. So no lead is safe with them."

Joseph Tugler committed a technical foul by reaching over the out-of-bounds line to knock the ball out of Sion James' hands with 1:14 left. Kon Knueppel hit the technical free throw, but instead of fouling Duke again, Houston played out the possession defensively. Tugler contested Knueppel's late shot clock layup, leading to Emanuel Sharp's 3-pointer with 33 seconds to cut the lead to 67-64.

In a sequence remarkably similar to Houston's comeback win over Kansas in January, the Cougars stole James' inbounds pass that led to Tugler's putback dunk with 25 seconds remaining.

"I think that one we sent Tyrese deep and it was Kon and Cooper," James said. "I had Cooper open, he had him sealed over the top and I just threw it too low. Big play at the time. And, honestly, probably a deciding play."

Houston's pressure defense had caused constant issues for Duke down the stretch, with Tugler's wingspan forcing James to make difficult inbounds passes or use timeouts.

"When they were inbounding the ball and it was almost a five-count, it gave me deja vu vibes. Like, this could happen again," said senior guard Mylik Wilson, comparing it to Houston's comeback win over Kansas when the Cougars rallied from down six with 10 seconds left to force double overtime. "Just keep playing hard and just trying to deny. And if they catch it, just try to up the pressure."

"I put JoJo on the ball," Sampson said. "We tried to deny. Encouraged him to throw it long because JoJo's wingspan is 7-6. I thought we could take everything over the top, force them to throw it east and west."

Proctor was sent to the free throw line, but missed the front end of a one-and-one. J'Wan Roberts boxed out Flagg, who was called for an over-the-back foul while going for the offensive rebound with 19.6 seconds left.

Roberts, who shot 3 for 8 from the free throw line in last year's Sweet 16 loss to Duke, went to the stripe and made both free throws to give Houston its first lead since the 15:25 mark of the first half.

"We didn't lose to Duke last year because of Jamal [Shead]'s ankle," Houston assistant Kellen Sampson said. "We lost because we didn't make free throws. We could have still beaten them last year if we'd have stepped up and made big free throws."

Duke's late-game issues were one of the big storylines of the first month of the season. The Blue Devils lost to Kentucky and Kansas in November, failing to execute down the stretch. They had been in a single one-possession game since their Nov. 26 defeat to the Jayhawks, though, but said all week they had watched film of late-game scenarios and were prepared if it happened again.

Down one with 17.2 seconds left Saturday, it was clear where the ball was going. Flagg had struggled on the final possessions in both of those losses, but Scheyer understandably had confidence the Wooden Award winner gave Duke the best chance to win.

Flagg faced up against Roberts on the left wing, drove left, then turned back toward the middle of the floor and got up a contested 12-foot turnaround jumper. It fell short and Houston corralled the rebound.

"It's the play Coach drew up," Flagg said. "Took it into the paint. Thought I got my feet set, rose up. Left it short, obviously. A shot I'm willing to live with in the scenario. I went up on the rim, trust the work that I've put in."

Said James: "We trust him in that spot 100 times out of 100."

Cryer hit two free throws with 3.7 seconds left and Proctor's desperation 3-pointer at the buzzer went long.

Comeback complete. Collapse complete.

The Blue Devils, who had produced the most efficient offense in college basketball since at least the 1996-97 season, made just one field goal in the final 10:30.

Though Duke's lack of offensive execution late in the game was the more obvious issue, Scheyer pointed to the Blue Devils' uncharacteristically poor defense as a key contributor in the blown lead.

"We could talk about not scoring down the stretch," he said. "For me, it's our defense. We gave up 42 points in the second half. That's what carried us in the first half. For me, as I reflect in the moment, I look at our defense. That was disappointing. Even if we're not scoring, usually we get stops to get separation."

The opening minutes of Saturday's game had all the hallmarks of a game that Sampson and Houston would want to play. Tugler got a hand on Flagg's first shot from the field, Houston had five offensive rebounds in the first four minutes and a loose ball that led to Wilson's layup and an early Houston lead.

The entire first half checked a lot of boxes that would, on paper, point to a Houston win.

Duke had multiple field goal droughts of more than four minutes and Flagg wasn't finishing consistently at the rim. Houston rebounded nearly 43% of its misses, grabbing nine offensive rebounds. And the Cougars had a 3-point barrage near the end of the half, burying three triples in the final 1:43 to bring their perimeter shooting percentage to 45.5% for the opening 20 minutes.

And yet, Duke entered the break with a six-point lead. The Blue Devils led by as many as 12 points in the first half, which was only the second time this season Houston trailed by double figures.

Duke also did it without getting a ton of production from its ancillary players. Khaman Maluach played just nine minutes in the first half, while James had a scoreless eight minutes. Proctor missed a couple of shots that would have extended an early Duke lead.

"We were really focused on those other guys," Sampson said. "We did a great job of not allowing Proctor to turn the corner and get in the paint off pin-downs. He's so good at that. We stayed down on every shot fake that he had. ... We did a great job on all the other guys. Knueppel, he made some tough 3s. Cooper Flagg, Cooper was not going to beat us by himself."

In the lead-up to Saturday's game against the Cougars' top-ranked defense, Scheyer stressed one thing: staying the course.

"I want us to be us," Scheyer said Thursday. "Let's be us and let's not be on our heels. I think that's an important thing when you play them. ... You really have to take advantage of that window of opportunity."

Duke did that -- for about 32 minutes.

But the Blue Devils, with the projected No. 1 pick in June's NBA draft and two other lottery picks, a team that entered the NCAA tournament and the Final Four as the favorites to cut down the nets, couldn't close out the win.

"More than anything, it's disappointment," James said.

He added: "We fully believe that we had the best team in the country and we had a chance to prove it."