Referee Felix Brych dismissed the Portugal international for violent conduct.
But despite his departure, Valencia failed to profit and lost 2-0. Miralem Pjanic scored from the penalty spot in each half to seal the victory.
With Manchester United winning 3-0 at Young Boys, Juventus sit second in Group G.
"I can only say that the video assistant referee would have helped the referee make the right decision," said Juventus coach Massimiliano Allegri after the game.
Ronaldo will miss next month's game against Young Boys in Turin. However European football's governing body, Uefa, could impose tougher sanctions on the former Real Madrid striker.
If a disciplinary panel decides a one match ban is too lenient, it could increase the suspension to three games. That would also mean Ronaldo's absence from the games against Manchester United at Old Trafford on 23 October and in Turin on 7 November.