Cristiano Ronaldo may miss a return to Old Trafford with Juventus on 23 October after he left the pitch in tears following a red card for violent conduct against Valencia. The striker stands to miss the Young Boys game on 2 October but Uefa could increase the ban.

Ronaldo, the Champions League’s all-time leading scorer with 120 goals, was dismissed after just 29 minutes following an off-the-ball incident but Juventus won 2-0 in Spain thanks to a pair of penalties from Miralem Pjanic

The forward appeared to put his hand on the head of Valencia defender Jeison Murillo, who fell to the ground. The referee, Felix Brych, showed 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 lying on the ground to express his disbelief. He was clearly distraught as he left the pitch, still shaking his head.

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 stoppage time but Daniel Parejo saw his effort saved by Wojciech Szczesny as Valencia were denied a consolation goal.

Renato Sanches scored the second goal for Bayern Munich against Benfica. Photograph: Octavio Passos/Getty Images

In Group F, Shakhtar Donetsk twice came from behind to draw 2-2 with Hoffenheim, who host Manchester City next on 2 October. Florian Grillitsch and Havard Nordtveit scored for the Bundesliga side, who brough Arsenal loanee Reiss Nelson off the bench late on. Ismaily Gonçalves dos Santos first brought the Ukrainian champions level before the substitute Maycon rescued a point with nine minutes left.

Ajax won 3-0 at home against AEK Athens in Group E. Nicolás Tagliafico was on target either side of Donny van de Beek’s goal for the Dutch side. Goals from Robert Lewandowski and Renato Sanches saw Bayern Munich win 2-0 at Benfica. Viktoria Plzen squandered a two-goal lead to draw 2-2 with CSKA Moscow in Group G. Michael Krmencik scored twice to put Plzen in control but Fedor Chalov pulled one back before an stoppage-time penalty from Nikola Vlasic rescued a point for the Russian side.