It looked like a routine play in the making, Austin Westlake’s Stephen Dawkins extending over Clark’s Aaron Durke for a fourth-down catch in the waning seconds Saturday.

The pass, if completed, would have kept Westlake’s fading comeback hopes alive with less than 10 seconds left, giving the Chaparrals one, if not two more shots from near the Clark 30-yard line to win or force overtime in the Class 5A Division I state quarterfinals.

But on this day — a day in which Clark captured its first regional championship by beating Westlake 24-21 on almost sheer determination alone — not even the routine could be taken for granted against the Cougars.

Somehow ripping the ball out of Dawkins’ hands with one fell swoop of his right arm, Durke got off the Alamodome turf with the ball in hand for an improbable, one-handed interception that sealed the game with 8 seconds left.

Earlier, fullback Jerrad White scored on a 14-yard run with 7:44 left for what proved to be the game-winner.

“I don’t know what it was,” said Durke, who also started at quarterback in place of injured Hayden Greenbauer, of coming down with the ball. “We both kind of had it for a second. Luckily, I came away with it.”

Only there was nothing lucky about how Clark (13-1) demoralized Westlake (9-5) to advance to next week’s state semifinals.

The Cougars will face Fort Bend Hightower at 4 p.m. Saturday at Royal-Memorial Stadium in Austin.

Clark executed its game plan to perfection, imposing its will against a Westlake team that at times appeared more physically gifted.

After falling behind 14-7 in the first quarter, Clark held onto the ball for a whopping 29 of the game’s final 36 minutes, including all but three minutes of the second and third quarters. Westlake ran just nine offensive plays over that stretch.

The Cougars engineered scoring drives that ate up 8:27, 9:30 and 4:30 — the last of which was capped by White’s winning score.

White finished with two touchdowns, while tailback Jock Tilghman had 144 yards and one TD on 34 carries to help Clark outscore Westlake 10-7 in the second half after the game was tied 14-14 after two quarters.

“This is just what we do,” center Robert Chapman said. “It’s what we practice, man. We just practice, practice, practice at that. I love it.”

Such resolve resonated throughout everything Clark did.

The Cougars went 5-for-5 on fourth-down attempts — all of which led to scores — while also holding Westlake on a pair of fourth-down plays in the fourth to protect their 24-21 advantage.

First, White converged in the backfield on Westlake’s Texas A&M-bound tailback, Ryan Swope, on a 4th-and-1 play from Clark’s 25. Bottled up, Swope tossed a lateral to QB Tanner Price, who was immediately brought down by lineman Neal Larson for a big loss.

And then there was Durke’s interception.

“They keep coming back, keep fighting hard,” said Cougars coach Lloyd Alexander, trying to fight back tears as he spoke to his players afterward.

“They play with so much heart, so much courage, desire and will. That makes up for a lot of mistakes.”