PULLMAN — On Senior Day at Martin Stadium, 25th-ranked Washington State beat No. 18 Stanford, 24-21, to notch its first home win over the Cardinal since 2007, and stay alive in its quest for the Pac-12 North title.

It also completed an undefeated 7-0 home record for the Cougars — a first in program history.

In a must-win game for both teams, the Cougars prevailed on the strength of their defense — which held the nation’s leading rusher, Bryce Love, to a season-low 69 yards on 16 carries, then got a huge interception by Frankie Luvu.

Luvu, a senior, picked off Stanford quarterback K.J. Costello with 15 seconds left in the game to preserve the victory and snap the Cardinal’s five-game win streak.

Falk rebounded from his benching against Arizona last week to finish strong in his final appearance at Martin Stadium, breaking Sean Mannion’s Pac-12 passing record.

The Cougars’ senior quarterback went 34 of 48 for 337 yards with three touchdowns, though he also threw one costly interception that Stanford linebacker Bobby Okereke returned for a touchdown in the third quarter.

This one was an entertaining back-and-forth encounter that featured several nail-biting moments for both sides. But ultimately, the Cougars prevailed.

Trailing Stanford, 21-17, in the third quarter after Okereke’s ran his interception back 52-yards for the score, WSU’s offense went through a perplexing dry spell, punting twice. The defense kept things close though, forcing consecutive three and outs to get the offense the ball back with 11:52 left in the fourth.

Slowly, but steadily, the Cougars offense emerged from hibernation to mount its best drive of the afternoon.

With Stanford only rushing four men and dropping everyone else into coverage, WSU’s running backs got some work. James Williams peeled off up the middle for a 12-yard gain, then later picked up another 9. Tay Martin was resplendent on the outside, hauling in a 17-yard pass on a crossing route, then caught a short ball for 3 yards and a first down.

Falk hit Jamal Morrow up the middle for 20 yards, then it was Morrow again, open in the flat, picking up 16 to get the Cougars to the Stanford 11.

Then, there it was, first-and-10, Falk hit Jamire Calvin in stride on another crossing route and the freshman receiver took off for the end zone, front flipping over the goal line for an 11-yard touchdown that allowed WSU to retake the lead — 24-21.

That 11-play, 94-yard drive burned 4:56 of clock. WSU’s offense would come out once more, but could not produce.

So with 35 seconds left, it fell to the defense to ice the win.

On first down, Nnamdi Oguayo pounced on Costello and dragged him down by the leg as he threw it away.

On second down, Costello’s pass to his tight end fell incomplete.

Third down proved to be the Cardinal’s undoing — Costello’s pass fell into Luvu’s waiting arms and electrified the sellout crowd at Martin Stadium.

Through Stanford’s first three offensive drives, WSU’s defense managed to bottle up Bryce Love, the nation’s leading rusher.