Groves successfully defended his WBA super-middleweight belt at the first time of asking against Cox.
The 29-year-old proved his power by downing his opponent in the fourth round with a brutal body blow with Cox unable to get back up in the count.
But it was the challenger who started brightest at Wembley’s SSE Arena, pinning Groves in the corner in the second round with a barrage of punches.
However, when Groves began to settle behind his jab it was the 31-year-old who began looking out of sorts.
And the defending champion stepped it up a gear in the fourth, delivering a heavy body shot sending Cox to the canvas.
Groves’ win sets up a mouth-watering bout with Eubank Jr and the two boxers faced off in the ring soon after the Chelsea fan finished his fight with Cox.
And Eubank Jr is now looking forward to delivering a fight the fans have been calling for.
“It was a good fight,” Eubank Jr said. “He did what he had to do. It looks like we are on for January, I’m excited.
“It was a nice little body shot. Jamie Cox, respect to him, he put on one hell of a show.
“Now we have got a super fight for the fans.”
