But nobody told that to burglar Gregory McCalium.
McCalium decided to break into his neighbour Frank Corti's home in Oxford during a long-running dispute over noise between the two.
Mr Corti is an old man of 72, so McCalium, aged 24 and armed with a knife, probably thought that Mr Corti stood no chance.
But what McCalium didn't know is that Mr Corti is a retired boxing champion who served in the British Army with the Royal Engineers.
So unfortunate McCalium was left with a black eye and a split lip.
To add insult to injury, McCalium was also sentenced to four-and-a-half years in gaol after the judge told him he got what he deserved.
Pictured: The battered and bruised face of a burglar who got on the wrong side of a 72-year-old former boxer
By Daily Mail Reporter
30th June 2009
A knife-wielding burglar had a shock when he attacked a pensioner in his home - and discovered his victim was a retired boxer.
Senior citizen Frank Corti, 72, a former junior boxing champion is still a bit handy with his dukes.
And when he spotted the aforementioned intruder, Gregory McCalium, 24, in his hallway he sprang into action and delivered two right hooks.
Battered and caught out: Gregory McCalium before his encounter with Frank Corti and after, looking ever-so-slightly the worse-for-wear
Reluctant hero: Frank Corti, pictured here with his boxing trophies, is pleased with the sentence and has insisted that 'most people would have acted the same way'
The blows were so powerful that McCalium, who had just lunged at Mr Corti with the knife, was left looking like he had been in 'a car accident'.
The pensioner then restrained him until police arrived. He was jailed for four and a half years yesterday after a judge told him he had 'got what he deserved'.
Glory days: Mr Corti pictured outside the Baliol Boys Club at the age of 16
After sentencing, Mr Corti said: 'I was scared when he first drew the knife but most people would have acted in the same way. If you can't defend what's yours, where are we at?'
Oxford Crown Court heard the break-in was the culmination of a long-running dispute over noise between the neighbours, who live in Botley, Oxford.
McCalium, a barman, was having a rowdy party at his house on August 18 last year when police turned up after a complaint from a neighbour.
McCalium assumed it had been made by Mr Corti - who won the National Association of Boys' Clubs Championship in Birmingham when he was 16 - and broke into his neighbour's home at 8am the following day.
Mr Corti, who was with his wife Margaret at the time, dodged out of the way of his attacker's lunge and punched him, giving him a black eye and a split lip, before subduing him.
McCalium was found guilty of aggravated burglary at a trial in March, during which he had claimed he could not remember the incident.
John Simmons, defending, said Mr Corti, who served with the Royal Engineers in North Africa from 1956-58, had received minor injuries during the confrontation.
He added: ' Photographs of the defendant showed what looked like a car accident and photos of the scene looked more like a murder scene.'
Recorder Angela Morris said: 'Luckily, Mr Corti was an able-bodied 72-year-old who was able to defend himself.
'The jury might well have concluded you got what you deserved when you entered that property and took a swipe at him with that weapon.
'The elderly and vulnerable people are entitled to demand the protection of courts from people like you who decide to take matters into your own hands and enter a property with a weapon.'
Mr Corti, a retired car worker, added: 'If needed to, I would do it again.'
During sentencing at Oxford Crown Court, Brian Payne, prosecuting, said: 'There was a struggle and it was clear Mr McCalium was intoxicated because his reactions were slow.
'It seems Mr McCalium ended up with far more serious injuries.'
Jailed: McCalium pictured partying on his Facebook page
After the sentencing, Detective Constable Jon Shaw said: 'Fortunately no-one was more injured in this incident but this was still a terrifying situation and McCalium must now pay for his actions.
'I hope that the victim, and his wife, might now be able to put this ordeal behind them and get on with their lives.'
During the trial, Mr Corti described how he had been woken during the night by noise from next door for several months before the incident.
Gregory McCalium had become involved in a long-running dispute with Mr Corti about noise
He told the court: 'They would slam the doors, then they would start partying. You could hear shouting, screaming and music.'
Mr Corti said he called police when he found McCalium banging on the front door of his house at about 6.30am.
Two hours later, he said, he came downstairs and saw bar worker McCalium in his hallway.
Mr Corti said: 'The accused produced a knife. It was no ordinary knife, it was more like a six-bladed knuckle duster.
'He made a slashing movement at me. I stepped back. He missed me, fortunately.'
Mr Corti said that while McCalium was off balance, he grabbed both of his wrists and managed to pin his arms against the wall.
He added he asked McCalium to drop the knife but he wouldn’t.
Mr Corti said: 'I shouted to my wife to ring the police.
'I was absolutely petrified.
'As I saw it, it was a matter of do or die so I let his wrists go. Fortunately the element of surprise was with me, so I adjusted my position and hit him with my right hand. It was just below the eye.
'I did not knock him out, but he was stunned. I heard the knife drop. We grappled.
I was trying to drag him out of the back door. We both fell to the floor. I had to subdue him by punching him, which I did not take a great deal of pleasure in.”
The jury heard he then lay on top of McCalium until the police arrived.