Chelsea midfielder Cesc Fabregas was shown a straight red card for a foul on new Liverpool signing Ragnar Klavan in a pre-season friendly in the US.
Fabregas, 29, saw red after 70 minutes at Pasadena's Rose Bowl after catching Klavan with a dangerous follow through.
Chelsea were 1-0 winners on the night, with defender Gary Cahill heading in after 10 minutes following a corner.
Liverpool boss Jurgen Klopp confirmed Fabregas went into Liverpool's dressing room after the game to apologise.
New Chelsea manager Antonio Conte also apologised for the challenge but insisted it was not intentional.
"I think that the fatigue sometimes can bring a player to go too late," he said.
"I know Fabregas is a good man, a good boy and is not a player to have this type of situation. I'm sorry for him, I'm sorry for the Liverpool player."
Klopp, meanwhile, has concerns over another new signing, Marko Grujic, after the midfielder was taken to hospital with suspected concussion.
Grujic suffered a collision with Bertrand Traore towards the end of the first half.
"The biggest problem for me in this moment is that Marko Grujic is in hospital, because he cannot remember anything. That's not too cool," added Klopp.
"Hopefully it's not too serious. Injuries after games like this in pre-season is the biggest problem."
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