A very timely post, geoquack. Cooper Kupp isn't the only player the Ducks faced before they were somebody. In 2007, fresh off a 55-24 thumping of Stanford at Palo Alto, the Ducks were home to face Cal, and a WR named Desean Jackson. All Jackson did was catch 11 passes for 161 yards and two touchdowns. Throughout the game and afterwards everybody was saying,"how did that guy burn us like that?"
The answer is because DeSean Jackson is really good. Numerous Pro Bowls and he holds the NFL record for most longer than 60 yards touchdown passes.
Another player that fits this mold is a TE who's name you might recognize. He played at Arizona and his name is Rob Gronkowski. In 2008 he caught 12 passes for 143 yards. Kupp, Jackson and Gronkowski had great games against the Ducks for a good reason.