Devastating Bayern Munich confirmed their status among the favourites for the Champions League with a 5-0 demolition of Dynamo Kiev on Wednesday while other big names, including holders Chelsea, struggled.
Robert Lewandowski's with a half double, Serge Gnabry, Leroy Sane and Eric Maxim Choupo-Moting after the break kept Bayern perfect in Group E while Barcelona's struggles continued with a second 3-0 loss, this time away to Benfica.
Munich's Eric Maxim Choupo-Moting (R) celebrates scoring his side's fifth goal with teammate Lucas Hernandez. Photo: Sven Hoppe/dpa.
Lewandowski broke the deadlock with a handball penalty then converted a slick pass from Thomas Mueller for his second.
Georgiy Bushchan made various saves but was well beaten by Gnabry high under the bar then caught out by Sane from a narrow angle.
Choupo-Moting's header completed the rout for impressive Bayern who are yet to lose a competitive game under coach Julian Nagelsmann, who said he was "satisfied for long stretches" and a "big step has already been taken" towards the knock-out phase.
Barcelona humiliated
Barcelona were improved compared to their 3-0 loss to Bayern on the opening day but fell behind to Darwin Nunez's solo effort in just three minutes and Rafa Silva pounced on a rebound in the 69th.
Nunez stroked in a penalty 10 minutes later to complete the humiliation and heap pressure increased on coach Ronald Koeman with his side bottom of the group.
"It's difficult to explain where we are," said Barcelona midfielder Sergio Busquets. "Games are won in both penalty areas and we weren't decisive at either end."
Luuk de Jong, though offside, bundling onto the post with the goal open summed up Barcelona, whose miserable day concluded with Eric Garcia's dismissal.
It was Benfica's first win over Barcelona since they clinched their maiden European title against them in 1961.
Ronaldo makes record
Cristiano Ronaldo made a record 178th Champions League appearance and capped his gala with an injury-time winner to beat Villarreal 2-1 to gain an element of revenge for defeat in last season's Europa League final.
Ronaldo, who overtook former Real Madrid team-mate Iker Casillas, stole an undeserved winner for United after a clever layoff from Jesse Lingard.
"I always had the feeling we could win the game," United midfielder Bruno Fernandes told BT Sport. "After the goal of Alex [Telles] the push from the fans was unbelievable.
"Some amazing saves from David [De Gea] to keep the score at 1-1. Then at the end... strikers have that feeling to score and Cristiano helps us again."
A wonderful volley from Alex Telles on the hour for the hosts had cancelled Paco Alcacer's goal almost immediately.
"Ronaldo is the kind of player who gets one chance and he takes it," said Villarreal defender Pau Torres. "That is what happened."
Chelsea
United are joint second in Group F on three points, level with Young Boys, who beat them on the opening day. Atalanta are top on four after edging the Swiss side 1-0.
Champions Chelsea dominated possession away to Juventus in Group H the Turin hosts claimed a famous 1-0 win thanks to Federico Chiesa just 10 seconds after the restart.
Juventus top the group on six points with Chelsea three behind, level with Zenit St Petersburg who crushed Malmo 4-0.
And RB Salzburg top Group G on four after two penalties - their fourth and fifth of the tournament - from Karim Adeyemi earned a 2-1 win over Lille. Wolfsburg and Sevilla both trail two points behind after a 1-1 draw.
