Cristiano Ronaldo has had a Champions League debut to forget with Juventus as he was sent off in the first half of their 2-0 win at Valencia while holders Real Madrid started their defence by beating Roma 3-0.
Ronaldo was dismissed in the 29th minute for a seemingly minor clash with Valencia defender Jeison Murillo.
Miralem Pjanic's pair of penalties gave Juve the win and they are second in Group H on goal difference behind Manchester United after their 3-0 triumph at Young Boys.
Real dominated Roma but had a nervous wait until Isco broke the deadlock on half time.
Viktoria Plzen were held 2-2 by CSKA Moscow in the other Group G game.
In Group E, Bayern Munich won 2-0 at Benfica after Ajax dismantled AEK 3-0.
There was a major shock in Group F as Manchester City lost 2-1 at home to Lyon after Shakhtar Donetsk drew 2-2 with Hoffenheim.
At Valencia, Ronaldo was left distraught when German referee Felix Brych consulted with the goalline official before producing the red card for an apparent pull at Murillo's hair.
Daniel Parejo, who conceded the first spot kick, missed an injury-time penalty as Valencia failed to get a consolation.
"We were playing very well until Ronaldo's sending off but we continued to play our football despite that blow and deservedly scored two goals," Juve coach Massimiliano Allegri said.
"I think the lads did very well tonight, especially because they played good football when we had to do that."
Manchester United were second best early at Young Boys but a brilliant Paul Pogba drive settled them and the French World Cup winner bagged his second from the spot before Anthony Martial completed the scoring.
Real are chasing a fourth consecutive title, now under new coach Julen Lopetegui and without Ronaldo, and started in determined fashion against Roma.
Isco curled home a glorious free kick at the end of the first half while Gareth Bale and substitute Mariano scored after the break.
"Real Madrid will always be Real Madrid, no matter who leaves. We keep on trying to win, keep on trying to score goals," Bale said.
Michael Krmencik's first-half double gave Plzen an advantage over CSKA but Fedor Chalov and Nikola Vlasic's late penalty rescued a point.
Manchester City were out of sorts against Lyon with Maxwel Cornet putting the guests in front, after Fabian Delph's air swing at a cross, and Nabil Fekir firing home when City lost possession in midfield.
Bernardo Silva pulled one back in the second half but the hosts couldn't find an equaliser with suspended manager Pep Guardiola watching from the stands.
"We didn't play with our usual intensity. We were not good enough tonight," Silva told BT Sport.
Hoffenheim were denied a victory in their maiden Champions League game at Shakhtar Donetsk as the hosts snatched a 2-2 in Kharkiv.
Florian Grillitsch and Haavard Nordtveit scored for the Bundesliga side but Ismaily and Maycon drew Shakhtar level twice.
Bayern triumphed in Lisbon on Niko Kovac's Champions League debut as coach with Robert Lewandowski and Renato Sanches, on his return to his former club, striking the goals.
"I'm pleased for Renato and us as a team," Kovac said. "What he has done in the pre-season was extraordinary."
Ajax are top of Group E, thanks to a double from Nicolas Tagliafico either side of Donny van de Beek netting against AEK.
Share
