Juventus believe they can win the Champions League with Cristiano Ronaldo, but they had to start by beating Valencia without him after he was controversially sent off on his debut in the competition for the Italian champions on Wednesday.

A tearful Ronaldo left the pitch in disbelief in the 29th minute, having seemingly aimed a kick at Valencia defender Jeison Murillo.

The Portuguese player then made contact with Murillo's head while urging him to get up.

Ronaldo dropped to the floor like the tournament was lost after German official Felix Brych brandished the red card but Juve showed more composure, Miralem Pjanic scoring twice from the penalty spot to clinch a comfortable 2-0 win.

Valencia were even awarded a third spot-kick of the match deep into injury-time but Daniel Parejo missed.

It remains to be seen how UEFA judge Ronaldo's offence, and dissent, but he is set to miss the next game at home to Young Boys on October 2.

After that comes the more threatening double-header against Manchester United.

"I can only say that VAR would have helped the referee make the right decision," Juventus coach Massimiliano Allegri said afterwards.

Valencia fans celebrated Ronaldo's dismissal at the Estadio Mestalla like a goal had been scored but, in truth, their team missed a golden chance to gain a foothold in Group H.

Instead, Ronaldo's absence had little effect. The Italians won with ease.

"You could say he's increased the players' desire," Allegri said. "He's raised the bar for everybody."

Juventus have claimed seven Serie A titles in a row but the Champions League is the one they want. They last won that in 1996 when Ronaldo was 11 and still playing youth football for Nacional.

Valencia fans lined the streets outside just to witness the buses pull in, booing the visitors and Ronaldo, in particular.

They also jeered him during the warm-up, during which Ronaldo replied by banging a ball into the open net from two yards.

Emre Can reacted to the dismissal of Cristiano Ronaldo in Juventus' 2-0 Champions League win over Valencia by saying "we are not women".

After watching a replay of the incident, Can told DAZN: "That's supposed to be a red?

"I just heard he said it was because of hair pulling. We're not women, we're playing football. If you're going to give a red for that, you can give a red for anything. It was 100 per cent not a red card."

Goalscorer Pjanic said that the sending off was "absurd".

"Football is a strange game. We could have been 4-0 up after the opening period, then came that absurd sending off," Pjanic said.

"It was like the Lyon game [in 2016]. We dug deep and found the spirit we needed to take us all the way to the final. That's what we need to do again."