Luke Falk threw for 407 yards and six touchdowns - all the scores in the first half - as Washington State riddled the Pac-12's top-ranked pass defense Saturday in a 52-31 victory over Oregon State in Pullman, Wash.

Falk completed 39 of 50 passes, including a game-high 11 to wide receiver Dom Williams for 158 yards and a pair of touchdowns, for the Cougars (4-2, 2-1 Pac-12), who have beaten their division-rival schools from Oregon on back-to-back Saturdays. Washington State also received two touchdown receptions from tailback Jared Morrow in rolling up 520 total yards and 32 first downs.

Seth Collins threw for 176 yards and a touchdown and ran for a game-high 124 yards and another score for Oregon State (2-4, 0-3), which suffered its third straight loss. Wide receiver Victor Bolden led the Beavers with 79 yards on six receptions and also scored on a 100-yard kickoff return.

The Cougars scored on all seven of their first-half possessions, also getting a 30-yard field goal by Erik Powell.

Following Powell's field goal, Bolden brought back the ensuing kickoff to pull the visitors to within 24-10 with 11:39 remaining in the first half, but Washington State countered with touchdown tosses from Falk to Morrow on back-to-back drives to extend the lead to 38-10.

After a scoreless third quarter, the Beavers turned an interception by safety Brandon Arnold into a touchdown, scoring on a 9-yard pass from Collins to wide receiver Jordan Villamin and a two-point conversion. Oregon State recovered the onside kick, but safety Shalom Luani picked off Collins and returned it 84 yards for a TD to seal the win with 3:45 remaining.