Lee Corso’s farewell to “College GameDay” was the most-watched episode of the ESPN Saturday morning staple in its nearly 40-year history.ESPN averaged 3.5 million viewers during the show on Saturday, preliminary Nielsen ratings show. It was broadcast from Columbus, Ohio, before the season opener between No. 1 Texas and No. 3 Ohio State. The Buckeyes won 14-7.The show also aired on ESPNU.ESPN reported that the ratings for the final 15 minutes of the show reached a record 5.1 million viewers. That’s the section of the show during which Corso famously made his prediction — who would win the game to be played in the city from which “GameDay” was airing — by putting on headgear representing his predicted victor.His final headgear choice was the first as the same one when the tradition began in 1996: the Buckeyes. For the record, it was the 46th time he put on the Ohio State mascot head, and the Buckeyes were 32-14.