SAN ANTONIO — Who said this NCAA Tournament lacked drama?

Saturday night produced one of the most memorable finishes in recent March Madness memory.

Cooper Flagg and mighty Duke, the favorites of this No. 1-seeded Final Four, are going home early.

Houston pulled a shocker, rallying from 14 down over the final 8:17 to advance to Monday night’s national championship with a riveting 70-67 victory over the freshmen-led Blue Devils at a buzzing Alamodome.

J’Wan Roberts’ two free throws with 19.6 seconds left gave the Cougars the lead for good and after Flagg missed in the lane, LJ Cryer sank two more from the charity stripe.

Tyrese Proctor’s desperation heave didn’t come close and Houston players ran all over the floor celebrating the hard-to-believe victory.

It will meet Florida on Monday night with a chance to win the school’s first national championship.

“I mean, it ain’t over because they still got time on the clock,” Cryer said. “As long as there’s time on the clock, we’re going out there and giving it our all.”

For so much of the night, it looked like Duke and its projected lottery pick freshmen were headed to the final.

They were up double digits. Flagg was in command.

But, Houston never let go of the rope. It kept on chipping away, even if it felt like it was destined to fall short.

Emanuel Sharp’s 3-pointer with 33.3 seconds to go made it a single possession game for the first time in the second half, and Houston stole the inbounds pass.

Joseph Tugler’s tip dunk cut it to one and Proctor missed the front end of a 1-and-1 at the other end. Flagg went over the back, sending Roberts to the line.

“Once we get the [lead to] three, now there’s game pressure,” Houston coach Kelvin Sampson said. “It’s a lot easier to finish the game when you have a 20 [point lead].”

Roberts, a fifth-year senior, was a 62.5 percent free-throw shooter, though that was up from 51.1 percent the year before.

In Duke’s Sweet 16 victory over Houston last March, he missed five of eight tries. He calmly made both, then forced Flagg into a difficult shot.

“To tell you the honest truth, going up to the free-throw line, I wasn’t really nervous at all just because of the work that I put in, just believing in it and trusting myself,” said Roberts, who had 11 points, 12 rebounds and five assists.

Houston’s top-ranked defense, its calling card, flipped the game. Duke (35-4) managed just one made field goal over the final 10:31 and eight points over the last 8:17.

The Cougars (35-4) manhandled them on the glass by 11, turning 18 offensive rebounds into 19 second chance points.

Cryer had 26 points to lead Houston and Sharp added 16. Flagg, the presumptive No. 1 pick in June’s NBA draft, notched 27 points, seven rebounds, four assists, three blocks and two steals.

“I’m heartbroken for a team that did everything for 38-39 minutes and came up short,” Duke coach Jon Scheyer said. “That’s the thing that kills me the most.”

Up six at the half, Duke stretched the lead to 14 with 11:54 to go.

It looked like it was on its way to a fourth double digit victory in five tournament games. Houston wouldn’t lay down, ripping off a 10-0 run to get within four.

It had a chance to get even closer, but Cryer missed a mid-range jumper, Proctor hit two free throws and Flagg nailed a 3-pointer.

He then swatted a Tugler layup attempt out of bounds. It felt like that had snuffed out the rally.

Houston, obviously, had other ideas.

“I said the same thing after we beat Gonzaga: You’re not just beating a good team, you’re beating an unbelievable program,” Sampson said.