Froch retained his world titles after Foster ended the contest in round nine when Groves was on unsteady legs.
However, Groves had dominated the fight up until that point and all three judges were scoring the contest in his favour.
Calzaghe was not impressed with the referee and he took to Twitter to vent his frustration.
Bull shit stoppage!!! !! Groves was winning!! Was shook up a bit. but stoppage?!?!.....Nah!!!!— Joe Calzaghe (@RealJoeCalzaghe) November 23, 2013