After Sebastian Janikowski put the Raiders ahead for good at 23-20 with a 47-yard field goal late in the third quarter, Campbell triggered a 16-point final frame with his TD toss to Reece.
Campbell ended the day with 238 yards and the one touchdown on 15-of-26 passing with two interceptions for the Raiders (7-7), who also got 119 yards on 20 carries from Darren McFadden.
Tim Tebow made his first career NFL start for the Broncos (3-11), but couldn't prevent their fifth straight loss.
He gained 78 yards and scored a touchdown while carrying the ball and completed 8-of-16 passes for 138 yards and another score.
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