Luke Falk threw five touchdown passes -- three in the third quarter -- as Washington State rallied for a 35-31 victory over Oregon State on Saturday night in Corvallis, Ore.

The Cougars twice took the lead from the Beavers in the second half, the final time on Falk's 1-yard touchdown pass to Robert Lewis with 10:19 left. That concluded an 80-yard drive by Washington State with Falk completing all four of his passing attempts for 43 yards.

Oregon State had two possessions after that but each time failed to gain a first down on fourth-down attempts, once at the WSU 38-yard line and later at the 34 when Ryan Nall was stopped for no gain, needing a yard to keep the drive going.

After losing the lead in the third quarter, Oregon State regained the advantage at 31-28 on Nall's 3-yard run, his third touchdown of the game. That came after the Beavers recovered a fumbled punt at the 3-yard line.

The Cougars, who remain tied with Washington for first place in the Pac-12 Northern Division at 5-0, trailed 24-6 at halftime but Falk completed 10 of his 11 passing attempts in the third quarter for 200 of his 415 passing yards. Two of his touchdowns in the quarter went to Gabe Marks as Washington State (6-2) took a 28-24 lead over the Beavers (2-6, 1-4) entering the fourth quarter.

Falk finished with 415 passing yards, completing 33 of his 46 attempts.

Oregon State took its 18-point halftime lead by running up 394 yards of total offense against the Cougars in the opening two quarters.

The Beavers jumped off to a 14-0 lead in the first quarter on two Nall touchdowns, immediately showing the value of his return to the lineup after he was limited to one rush in the previous two games because of a foot injury.

Nall's first touchdown was an 89-yard run on Oregon State's second possession, the third-longest rushing touchdown in school history. Nall also scored on a 19-yard pass from Marcus McMaryion, who was 23 of 39 for 327 yards and two TDs.