PULLMAN — Washington State entered Saturday night’s season opener against Eastern Washington hoping to end a disturbing streak of four straight opening day losses under Mike Leach.

Unfortunately for the Cougs, that streak will live on for another year.

EWU rode a huge 12-reception, 206-yard, three-touchdown performance from its Walter Payton Award-winning receiver Cooper Kupp to a 45-42 win at Martin Stadium, and became the second-straight FCS team to stick it to the Cougs in as many years.

Players and coaches seemed at a loss to explain exactly what had gone wrong and why it was they always stumble out the gate.

“We can’t get a home opener win for the life of us, it seems like,” said junior linebacker Peyton Pelluer, who led the Cougs’ defense with 10 total tackles. “We were very optimistic for this game. The energy was incredible for the whole week. This stings but we’re going to bounce back and respond.”

The Eagles trailed throughout the first half, but managed to keep things close, matching WSU score for score to go into halftime down 28-24.

After the half, EWU broke the game open in what became a nightmare of a third quarter for WSU.

“They dominated the third quarter,” Leach said. “They executed better than we did. I think those guys were more disciplined about doing their job and dealing with adversity than we were.

“The best player on the field was Cooper Kupp, and the second best player was their quarterback whose name I can’t pronounce.”

The Eagles’ sophomore quarterback Gage Gubrud put up big numbers in his first career start. He finished 34 of 40 for 474 yards, five touchdowns and an interception and rushed for 77 yards on 14 carries — 30 of which came on a touchdown run with 1:39 left in the game that served as the knockout blow.

Led by Gubrud’s breakout performance and another stellar outing from the record-setting Kupp, the Eagles outscored WSU 14-0 in the third quarter to lead the game 38-28. Kupp, who returned to EWU for his senior season instead of going out for the NFL, showed the sellout crowd of 32,952 fans at Martin Stadium exactly why he was predicted to go in the second round of the 2016 NFL draft.

Kupp’s first touchdown of the night came in the second quarter, when he caught a short pass from Gubrud and simply outgunned WSU’s freshman safety Jalen Thompson, who was the only man in position to make a tackle as Kupp powered 75 yards into the end zone to even the score 21-21.

In the third quarter, the Cougs defense perplexingly left Kupp alone in the middle of the field, and Gubrud made them pay for the error, lofting a 26-yard pass to his favorite target to give EWU a 31-28 advantage over the Cougars and their first lead of the game.

Things just unraveled for WSU at that point.

With EWU mounting yet another offensive assault, Cougars junior Robert Taylor, who was filling in for Shalom Luani at free safety went in headfirst on a tackle of Eagles receiver Shaq Hill on the end of a catch and was ejected from the game for targeting.

Leach conceded that not having Luani in the lineup “probably did impact the game a little bit,” but the defense adamantly maintained that his absence wasn’t the cause of their problems.

“It shouldn’t matter,” Pelluer said. “We should be able to help him out up front — me personally — and give him, whoever’s in there, the confidence to play.”

Sophomore Hunter Dale replaced Taylor at free safety, and the Eagles seized their opportunity and struck again. Gubrud found Kupp in the back of the end zone and the receiver pulled down a 7-yard pass with his left hand over the shoulder of WSU cornerback Darrien Molton.

Suddenly the Cougars, who went into the season highly regarded after last year’s 9-4 success, were down 38-28 to an FCS team, in a situation reminiscent of last year’s shocking season-opening loss to Portland State.

But ultimately, the Cougs were undone by their own mistakes.

Luke Falk went 41-of-51 for 418 yards and four touchdowns, with one interception, and Gabe Marks had 10 receptions for 108 yards and two touchdowns.