PORTLAND, Ore. - UC Davis used a stellar second-half defensive performance and overcame the loss of starting quarterback Greg Denham to rally for a 34-to-31 win at Portland State University.

The Vikings offense started hot, scoring on its first three possessions, and led 21-17 at the half. At that point, Portland State had 220 yards of total offense. From there, though, the Aggies controlled the game, and held PSU to just 17 yards in the second half.

Portland State (2-6) opened up a 28-17 lead early in the third quarter when Ryan Rau picked up a UC Davis fumble and ran it back 27 yards for a touchdown. Ryan Pedersen's hit on the Aggies' Denham not only caused the fumble but also knocked the junior signal caller out of the game.

The Vikings appeared to have the momentum, but UC Davis scored on their first play of the fourth quarter on a 30-yard pass from Austin Heyworth to Bakari Grant. It was the start of 17-point quarter that gave them a 34-31 advantage.

With a little over three minutes to go, Portland State had the Aggies backed up on their own five-yard line and in a 3rd-and-14 situation. The Vikings had UCD running back Josh Reese wrapped up for a loss, but Reese escaped for a 31-yard gain and the Aggies ran out the clock from there.

Heyworth came on in relief and went 6 of 7 for 82 yards and two TDs. Denham passed for 259 yards and a score, completing 20 of his 35 attempts.

On their first drive of the game, the Vikings benefited from two big plays. Connor Kavanaugh scrambled for 30 yards to put the ball at the UC Davis 39. Two plays later, Bobby McClintock rumbled 30 more yards for a touchdown on a screen pass to make it 7-0.

UC Davis (4-3) answered back with a 76-yard drive and tied it up on a four-yard touchdown run by Joe Trombetta. The Vikings then went back on top on a one-yard score by McClintock with 2:14 left in the first quarter.

The teams traded scores again to make it 21-14 in favor of Portland State. The Aggies appeared on their way to tying it up, but Trombetta fumbled at the two-yard line after getting hit by Siasau Matagiese and Cody Worthen pounced on the loose ball to give PSU possession.

The Aggies forced Portland State to go three-and-out, and got the ball back with 59 seconds until the break. Sean Kelley's 35-yard field goal as time expired pulled the Aggies to within four at 21-17.

Making his second career start under center, Kavanaugh went 12 of 18 for 131 yards and two TDs. He also led the Vikings with 50 yards rushing on 13 carries.

Mike Williams led the Vikings' defense with nine tackles. Worthen and Jaycob Shoemaker had seven and six tackles, respectively.

UC Davis finished with 484 yards of total offense, including 341 through the air. The Aggies got 143 yards on the ground, including 84 from Reese on just six rushes.

Portland State heads to Seattle next Saturday to face Eastern Washington in a Big Sky Conference matchup. Kickoff is set for 1:05 p.m. at Qwest Field.

GAME NOTES: UC Davis won its third in a row in the series, but PSU still has a 6-4 lead ... The Aggies lost all three of their fumbles while the Vikings recovered all three of theirs ... Ray Fry and McClintock each had five catches ... Chris Carter led UC Davis with nine catches for 83 yards ... Zach Brown kicked a 30-yard field goal in the fourth quarter for the Viks. It was his 13th of the season, which is the third-most in a single-season at PSU. He has made nine in a row.