Cristiano Ronaldo and Lionel Messi could both end matchday 2 of the Champions League without having socred in this season's competition. What could happen to any other player is something paranormal between for thse two.
We have to go back to 05-06 to find Champions League group stage matchdays that the Portuguese and Argentinian didn't score in. Messi had already played one Champions League match before these two games (matchday 6 in 04-05, which ended 2-0 to Shakhtar Donetsk). From 05-06, it has been steady, as it has for CR7.
While it is true Ronaldo and Messi have missed some of these matches due to injury, if one didn't score the other did. If Juventus don't score against Bayer Leverkusen and Barca fail to score against Inter (Messi might not even play due to injury), something will have happened for the first time in 14 years.
'ProFootballDB', BeSoccer's resident statisticians, have examined the evolution of Messi and Ronaldo's goals in the Champions League. 2 absolute greats.