After all, the sending off could see him miss a huge game with Manchester United that would prove a crucial match in the group stages as well as a fairytale reunion.
The referee got a word in his earpiece from the goal-line official behind the goal and the referee unceremoniously produced the red card for Cristiano Ronaldo.
Ronaldo was dismissed after a clash with Jeison Murillo was spotted by the assistant referee and communicated to German referee Felix Brych, who drew a red card from his top pocket.More news: Startled camel stampedes through Pittsburgh circus, injuring 6 children
Rio Ferdinand was one of many to react to the decision, tweeting that Ronaldo should appeal and also discussing the episode during his duties as a pundit.
Here are three thoughts from Wednesday's action in the Champions League.
With the suspended City manager Pep Guardiola forced to watch from the stands, Fekir the made it 2-0 to the French side in the 43rd minute with a sweetly struck drive after being set up by Memphis Depay.More news: Russian Federation presents new proof that Ukraine downed MH17 flight in 2014
"It was a small incident, a simple case of hooliganism", said local government delegate Juan Carlos Fulgencio in an audio statement sent to Reuters.
Real Madrid got their title defence off to a strong start by convincingly beating Roma 3-0 at home.
Such questions have been replaced by bullish confidence, just in time for Juventus to launch its Champions League campaign away to Valencia.
Valencia threw numbers forward in search of an equaliser, and they were awarded a penalty late on but Parejo saw his spot-kick saved by Wojciech Szczęsny as Juve ran out 2-0 winners on the night.More news: US Open chair umpire Carlos Ramos says he is fine