With Chelsea leading 1-0 in the European club showpiece in Porto thanks to a Kai Havertz goal, Rudiger blocked the path of De Bruyne as the Belgian attempted to burst past him and collect a pass in the Chelsea half. 

Both men fell to the floor, although it was De Bruyne who came off worse as his head appeared to connect with Rudiger’s shoulder.

The Man City skipper lay prone on the turf at Estadio do Dragao for several minutes as he was attended to, before slowly being helped to his feet with bruising already visible underneath his left eye.

De Bruyne was gingerly helped off the pitch in tears, clearly shaken by the impact and unable to continue as he was replaced by Gabriel Jesus.

Rudiger was also eventually helped to his feet by referee Antonio Mateu Lahoz, who immediately brandished a yellow card in the German’s direction.

Online, meanwhile, fans were accusing the Rudiger – who was wearing a mask to protect a facial injury of his own picked up in the semi-final first leg with Real Madrid – of a “dirty” deliberate challenge.

Some likened the incident to the famous rough treatment dished out by Real Madrid captain Sergio Ramos on Liverpool’s Mo Salah in their Champions League final in 2018.

Rudiger’s challenge deprived City of De Bruyne for the final 30 minutes of normal time in Portugal, and was another crucial moment involving the 28-year-old centre defender after his vital first-half challenge on Phil Foden when the City man was well-placed to score.

Chelsea are chasing a second Champions League title to add to the one they claimed in Munich in 2012, while City were appearing in a maiden final in Europe’s biggest club game.    

Earlier in the game, Chelsea had lost their skipper, Thiago Silva, after the Brazilian was forced off in tears after 39 minutes with an apparent muscle injury.