A 71-year-old former army boxing champion who was attacked by a 6ft 4in thug half his age floored him with two right hooks, a court heard.
Pensioner John Cokeley was at home watching TV in his slippers when he heard Mark Pearce, 34, rowing with his neighbour.
Mr Cokeley, who is 5ft 10in, went outside and told burly Pearce to calm down – but was punched in the face.
Pearce hit Mr Cokeley in the head – smashing his glasses and giving him black eye, a court heard.
But the pensioner, a professional welterweight undefeated boxer in the Army, got up and floored Pearce with a massive "roundhouse blow".
Pearce managed to get to his feet but Mr Cokeley gave him a second blow to the stomach – flooring him again. That punch kept him down and Pearce was still laid out with a dislocated shoulder when police arrived to arrest him.
Pearce denied causing actual bodily harm claiming he was attacked by the ex-boxer and was acting in self-defence. But he was found guilty, and yesterday sentenced to a six-month prison sentence suspended for two years at Exeter Crown Court.
Pearce was also given a 12-month supervision order and ordered to pay £175 costs.
The court heard Pearce was having an argument with one of Mr Cokeley's neighbours at a block of flats in Torquay on April 25.
Mr Cokeley, a former soldier who served around the world with the Army from 1957 to 1968, went to investigate to try and calm the confrontation.
Mr Cokeley who is twice the age and six inches shorter, was attacked but managed to knock Pearce to the ground twice. Both men were taken to hospital with Mr Cokeley suffering a cut to the head and Pearce nursing a dislocated shoulder.
Recorder Brian Lett QC told Pearce it was "a disgraceful incident" despite Mr Cokeley being "remarkably fit for his age".
He said: "He was able to call upon his professional training of many years to fight back.
"You assaulted him, the peacemaker, which I can only describe as serious."
Pearce told the court he was "afraid" he was going to be injured by the ex-boxer, despite his age and size.
Pearce, of Paignton, Devon, was cleared of common assault on neighbour Robert Kell in the confrontation which led to the attack.