A 34-year-old man admitted throwing the single punch which left his friend in a coma and with permanent mental damage.
Graham Hull pleaded guilty to inflicting grievous bodily harm on Kirk Wearing, which left him with lasting problems.
Mr Wearing was hurt when his head hit the ground following the attack and left him with “serious injuries, needing life-saving surgery”.
Hull, who has committed previous offences of violence and of public disorder on his record, admitted the offence on the day his trial was due to start at Teesside Crown Court.
He entered his guilty plea after warrants were issued for the arrest of two witnesses who had previously been reluctant to attend court, and after it was decided his previous convictions for violence would be put before the jury.
Mr Wearing, 30, was in a coma for several weeks following the attack near the junction of Cornwall Street and Uppingham Street, Hartlepool, on October 30.
“The injuries were sustained after Mr Wearing fell to the ground and hit his head,” said Simon Reevell, prosecuting.
“They were serious injuries, needing life-saving surgery.
“Mr Wearing has made a degree of recovery.”
Hull and Mr Wearing had earlier visited the Premier store in Shrewsbury Street, where both attempted to steal drink.
Mr Wearing was successful, but Hull was not.
Following the punch a few hundred metres away, Hull returned to the shop and was captured on CCTV talking to the shopkeeper, and indicating a punching movement.
The prosecution claim Hull told the shopkeeper he had punched the man who has just stolen the drink.
Hull, of Stockton Road, Hartlepool, admitted inflicting grievous bodily harm.
He has previous convictions for offences of violence and of public disorder.
The Recorder, Mr Tahir Khan, and prosecuting and defence barristers agreed the case fell into ‘level two’ of the sentencing guidelines, with a range of one to three years of imprisonment.
Mr Reevell said Mr Wearing and his mother were not present in court, but wished to be present when Hull is sentenced.
Recorder Khan ordered a pre-sentence report, and the recorder adjourned the case until April 13 when sentence is expected to be passed.
Hull was remanded in custody.