After dropping the Argentine with a fierce body shot late in the second, Groves finished the job with a right hand over the top of Balmaceda which led to the fight being called off.
Groves is expected to be presented with bigger tests on the undercard of Carl Froch v Mikkel Kessler II on May 25 at the o2 Arena, and then again in the autumn, as he looks to resume his climb towards a world title shot under Eddie Hearn.
In the main event, Darren Barker continued his return following a world title defeat to Sergio Martinez by crushing Simone Rotolo in middleweight action.
Barker won his first bout in over a year against Kerry Hope at London's Olympia in December and continued his path towards a second world title opportunity in accomplished fashion.
Putting the Italian to the canvas with an uppercut and body flurry in round one, the Londoner continued the barrage until Rotolo did not come out for the fifth round due to a hand injury.
Welterweight Lee Purdy dominated Cosme Rivera, a late replacement for the unwell Carson Jones, earning a ninth-round win when the referee and doctor agreed Rivera should not continue.
After picking up an early knockdown in the opening round, Purdy opened up Rivera and weathered a decent round from the Mexican before bloodying him further for the win.
Danny Connor retained the Southern Area light-welterweight strap against Chris Evangelou in a rematch from Alexandra Palace in September.
Evangelou appeared to have the better of the first bout for the vacant belt only for Connor to be awarded the win, but ‘Cassius’ was far more convincing the second time around en route to success.
China Clark claimed the English cruiserweight title in a brutal battle with Wadi Camacho. The unbeaten pair traded vicious blows for seven rounds before Camacho’s corner pulled their man out of action, handing the belt to the Leeds man who floored the Londoner in the sixth.
Liam Shinkwin claimed his first pro honours in a great fight with Ryan Taylor for the Southern Area lightweight belt – with Shinkwin’s classy work earning the win in the eyes of referee John Keane who raised his hand to the tune of a 97-93 win.
There were eight-round successes for John Ryder and Erick Ochieng, while Martin J. Ward celebrated stepping up to six-round action by recording his first win inside the distance, getting Kevin Hanks out of the way in five.