Ronaldo, the Champions League's all-time leading scorer with 120 goals, was dismissed after just 28 minutes following an off-the-ball incident.

The forward appeared to put his hand on the head of Valencia defender Jeison Murillo, who fell to the ground. Referee Felix Brych gave Ronaldo a straight red card after discussing the incident with his assistant behind the goal.

The Portugal captain looked baffled and kept protesting his innocence, briefly laying on the ground to express his disbelief. He was clearly distraught as he left the pitch, still shaking his head.

It was his first red card in 154 Champions League games and it means he is set to miss a return to Old Trafford when Juventus play his former club Manchester United next month.

Despite their numerical disadvantage, Juventus scored both of their goals without their star man with Pjanic tucking away his spot kicks in the minutes either side of half-time.

There was a third penalty in the match deep into injury time but Dani Parejo saw his effort saved by Wojciech Szczesny as Valencia were denied a consolation goal.

The other game in Group H saw Manchester United run out comfortable 3-0 winners in Switzerland against Young Boys. Paul Pogba struck twice in the first half, the second coming from the penalty spot, before Anthony Martial scored midway through the second half.

Pep Guardiola could only watch as Manchester City slipped to a surprise 2-1 defeat in their Group F opener against Lyon.

The City boss was sat in the stands at the Etihad Stadium due to a touchline ban and his side lacked their usual dynamism as they gifted first-half goals to Maxwel Cornet and Nabil Fekir.

Bernardo Silva pulled one back as City rallied after the break but they could not force an equaliser in an underwhelming start to their campaign.

Earlier in City's group, Shakhtar Donetsk twice came from behind to draw 2-2 with Hoffenheim, who scored goals through Florian Grillitsch and Havard Nordtveit.

dos Santos Ismaily first brought the Ukranian champions level before substitute Barberan Maycon rescued the hosts a point with nine minutes left.

The other early kick-off saw Ajax win 3-0 at home against AEK Athens. Nicolas Tagliafico was on target either side of Donny van de Beek's strike for the Dutch side.

Later in Group E, goals from Robert Lewandowski and Renato Sanches saw Bayern Munich win 2-0 at Benfica.

Holders Real Madrid made a winning start in Group G as goals from Isco, Gareth Bale and Diaz Mariano gave them a 3-0 victory against Roma at the Bernabeu while Viktoria Plzen squandered a two-goal lead to draw 2-2 with CSKA Moscow.

Michal Krmencik scored twice to put Plzen in control but Fedor Chalov pulled one back before an injury-time penalty from Nikola Vlasic rescued a point for the Russians.