The 36-year-old, who stopped Groves in a highly debated ninth round victory in November last year, proved that he was simply a class above the challenger with a fantastic right-hand finish in the eighth.
Both fighter’s had their moments early on, although Groves took the first three rounds on sheer volume of punches, whilst Froch came on strong from rounds four to six – which saw the pair begin to exchange more in replication of the first fight.
In the seventh, Groves rocked Froch with a straight left hand which seemed to indicate that the Londoner may begin to get the upper hand on the unified title holder, although nobody could have foreseen what was to come.
A massive right hand over the top from Froch connected on Groves jaw as he tried to throw his own shot and there was no recovery from what was a shuddering hit, and probably the best punch ever connected by ‘The Cobra’ to date.
Groves, 26, was sprawled on the canvas motionless, with his leg caught on the ring apron, as referee Charlie Fitch waved the fight off immediately without a count.
‘The Saint’ attempted to get up once the fight was called off but was in no position to continue and this time around there was no controversy.
The physician at ringside administered oxygen to Groves once he had realized just what had transpired and Froch then began to celebrate an amazing triumph in front of a satisfied crowd at the National Stadium.
Froch now potentially moves on to another big UK battle with James DeGale, whilst Groves can come again after proving beyond doubt that he belongs with the world-class operators of the division, not once but twice.
Follow on Twitter @PhilDJay for tweets of upcoming news on WBN