PULLMAN — Six years into the Mike Leach’s tenure at Washington State, the Cougars have their marquee win.

In Pullman on a Friday night game broadcast nationally on ESPN, the 16th-ranked Cougars pulled off the upset of a generation, stunning No. 5 USC 30-27 to snap the Trojans’ 13-0, year-long winning streak.

It marked WSU’s first regular-season win against a top-five team in 25 years, and it could vault the Cougars into the top-10 when the next set of rankings are released Sunday.

The win gave Luke Falk his first victory over USC in his career. It’s memorable when you consider that Falk became WSU’s starting quarterback the last time USC visited Martin Stadium in 2014, when Conner Halliday suffered a broken leg in the first quarter against the Trojans, and Falk became the Cougars’ quarterback.

On Friday night, Falk outdueled Heisman Trophy candidate Sam Darnold, completing 34 of 51 passes for 340 yards and two touchdowns.

Darnold meanwhile was a pedestrian 15 of 29 for a season-low 164 yards, and did not throw any touchdowns though he ran for two.

The game was evenly played from start to finish, with six lead changes.

But what stood out was WSU’s defense, which harassed Darnold and the Trojans throughout the night, despite losing middle linebacker Isaac Dotson in the first quarter to an unspecified leg injury.

In his second career start, freshman linebacker Jahad Woods came up with the biggest play of the game when he sacked Darnold on second-and-10 from the USC 24 with a little over a minute remaining to force a fumble that WSU recovered.

Down 27-20 with about 6:30 left in the fourth quarter, USC appeared to be fighting a losing battle against a resilient Cougars defense that had held quarterback Sam Darnold to 100 passing yards to that point.

But on fourth-and-13 from the Cougar 42, the Trojans made a gutsy call to go for it.

Darnold stood strong in the pocket and released the ball just as he was leveled by a WSU defender, but the pass was true and ended up in the hands of Tyler Vaughns for a 14-yard pickup and a first down.

On the next play, Darnold went back to Vaughns for a 26-yard pickup that set up first-and-goal from the 1.

It took only two more plays for Darnold to run into the end zone and tie the score at 27.

However, the Cougars weren’t done. They got the ball at the USC 25 with 5:01 left, and rode runs of 11 and 22 yards from Jamal Morrow to set up Erik Powell for a 32-yard go-ahead field goal.

With 1:40 left on the clock, the game was in the hands of their defense, and it came through with Woods’ big play.

Two series, one on offense and one on defense, stood out as the Cougars went into halftime with the score tied 17-17

But first, to set the stage.

The Cougars’ offense once again fell victim to a slow start, something that has plagued them for most of the season.

And while the defense held its own against the Trojan offense for most of the first half, one big breakdown in the second quarter cost them dearly. On third and four from the Trojans’ own 14, Ronald Jones II somehow found a hole on the right side and he turned on the afterburners and outran the entire WSU defense on an 86-yard touchdown run that put USC up 14-10.

No big deal right?

Sure. But after taking a holding penalty on the end of Robert Taylor’s kickoff return, the Cougars started their offensive drive deep in their own territory on the 10-yard line.

Then, to compound matters, on the very first play of that drive, USC’s Uchenna Nwosu — who entered the game with a team-high eight pass breakups — picked off Falk at close range.

Suddenly, the Trojans’ offense had the ball at the WSU 3-yard line in what appeared to be a surefire touchdown situation. A touchdown would have put them up 21-10 on WSU midway through the second quarter.

But the Cougars’ defense made a statement. On first down, it held Ronald Jones to a gain of 1 yard. On second down, freshman cornerback Marcus Strong jumped in front of the receiver in the end zone and got his hands on the ball and couldn’t hold on to make the interception. On third down, Nate DeRider — who replaced an injured Isaac Dotson at middle linebacker earlier that quarter — sniffed out the run play and enveloped Stephen Carr for no gain.

The Trojans settled for a 20-yard field goal from Chase McGrath, but the sell out crowd of 33,773 roared as the WSU defense celebrated its big goal line stand.

That energy seemed to energize the Cougars. But the offense didn’t start clicking until the final drive of the second half when it mounted what might be the best offensive drive the Cougars have had all year.

Trailing USC 17-10, with 4:56 left in the half, the Cougars started at their own 6 yard line and methodically and purposefully pushed up the field.

Like a boxer picking his shots, Falk stealthily mixed in a combination of check downs to his backs and inside receivers, with some called run plays, and even scrambled for a 10-yard gain as the misfiring Cougars finally found a rhythm.

Seven different offensive skill players touched the ball that drive. There was Kyle Sweet with the 12-yard gain on second-and 7. Then it was a James Williams reception for 13 yards up the right sideline. Jamire Calvin got in on the action with some jitterbug moves to turn a short pass into a nine-yard gain, and Jamal Morrow had a 13-yard scamper.

The Cougars got some help from USC DB Jack Jones, who drew a defensive pass interference penalty against Tavares Martin that set WSU up on the USC 2-yard line.

It took three tries. But on third-and-goal from the 1, after back-to-back timeouts from WSU and USC, Falk faked a fake handoff and pretended to pass. USC took the bait, and Falk then handed the ball to Morrow who ran into the end zone for a 1-yard touchdown that tied the game.