Chelsea striker Diego Costa has been banned for three matches by the Football Association after failing with his appeal against a violent conduct charge for a stamp on Liverpool's Emre Can on Tuesday.
Spain international Costa was challenging for the ball by the touchline in the first half of the second-leg tie at Stamford Bridge when he forcefully stood on Can's shin.
The incident went unpunished during the match, which Chelsea won 1-0 to progress 2-1 on aggregate, as referee Michael Oliver did not see the challenge.
The FA subsequently charged Costa with violent conduct, a decision the player contested.
However, an FA Independent Regulatory Commission upheld the original ruling and handed out a three-match ban.
"Diego Costa will serve a three-match suspension with immediate effect after a charge of violent conduct against him was found proven by an Independent Regulatory Commission on Friday 30 January 2015," an FA statement read.
"The Chelsea forward had denied the charge in relation to an on-field incident involving Liverpool's Emre Can which occurred in the 12th minute of the League Cup semi-final second leg at Stamford Bridge on Tuesday 27 January 2015.
"The incident was not seen by the match officials but caught on video."
The news is a huge blow to Chelsea ahead of Saturday's top-of-the-table clash with Manchester City at Stamford Bridge.
Costa is also set to miss out on the trip to Aston Villa on February 7 and the home match with Everton four days later.
Chelsea manager Jose Mourinho defended Costa after the game and the ban is sure to irk the Portuguese, who stated the coming together with Can was "accidental".
Mourinho said: "Maybe you [the media] are already influenced by the campaign on the television with certain pundits saying that Costa has crimes - they must be nuts, the guy who says that.
"I have to say that he goes for the ball, he chases it, the opponent [Can] goes to the floor and he puts his foot there when he is looking at the ball... What you call stamps, and Sky calls crimes, I have to say accidental."
Liverpool manager Brendan Rodgers took a different view of the incident, and called for the FA to take action.
"These things happen in the game but I think anyone watching it would not like to see what we've seen Diego Costa do," Rodgers told Sky Sports.
"Not just on Martin Skrtel but on Emre Can, a young player who was clearly stamped on. You don't want to see that. There's no need for it."
Costa has proven an instant hit at Stamford Bridge, scoring 17 Premier League goals since joining in a big-money move from Atletico Madrid in the close-season.
However, his on-field behaviour has come under the spotlight due to Costa picking up eight bookings in all competitions, including a caution in a 6-3 win at Everton in August where he squared up to goalkeeper Tim Howard.