For most of the first half, the lowly Buffs showed that they could compete with Pac-12 opponents better than they could last year.  The rain slowed down the passing game on both sides as Oregon State quarterback Sean Mannion reverted to his fallible former self in the first half with two early turnovers and a sub-50% completion ratio .  Colorado could not find the end zone throughout the half, however, failing to capitalize on its opportunities or exploit star wide receiver Paul Richardson.  Mannion finally erupted near the end of the half with a bold fourth-down conversion and third-down touchdown pass.  (He would complete six touchdown passes by the end of the day, setting a single-game Oregon State record.)  That end-of-half surge seemed to deflate the Buffs, perhaps reminding them of struggles past.  Or perhaps they could not bring their crispest focus to football after the devastating floods in their region.  While the Beavers delivered their first convincing victory of the season, the Buffs head home knowing that they have made progress but not a huge leap forward.