The Stevenage fan who ran on to the pitch and punched defender Scott Laird after the team's 3-1 win over Newcastle has been jailed for 12 weeks.
Robert Fitzgerald has also been banned from attending football matches in both England and Wales for six years after the incident which occured in the aftermath of Stevenage's shock FA Cup win on January 8.
Stevenage Magistrates' Court was told the altercation occurred because Laird had previously been involved with Fitzgerald's current girlfriend and "not treated her correctly".
Fitzgerald's girlfriend Jade Coles, who is pregnant, wept today as the 24-year-old was led away from the dock.
"The offence was fuelled by alcohol," magistrates' chairwoman Linda Nadauld said. "It has become clear from the television evidence that you made a beeline for this particular player.
"We have also heard evidence that a steward noticed disorderly behaviour from you directed towards Mr Laird.
"The victim was in a vulnerable position as he was in the location to fulfil his duties as a professional football player.
"The attack was unprovoked and unexpected. The court must impose a deterrent sentence to stop this type of behaviour and conduct on a football field."
Prosecutor Phillip Mansefield revealed to the court Fitzgerald was seen "throwing or spitting'' a drink and also throwing a hamburger at the player during the game.
Post-match, he ran onto the pitch and was seen to punch Mr Laird "with such force" he fell to the floor.
Laird later had no memory of how he returned to the changing room, and was left with swelling on his left jaw after the punch.
In an impact statement read to the court, Mr Laird said: "I'm concerned that if the male who did this to me is allowed back into the ground that it might happen again.
"I just want to play football well and enjoy the celebrations when we win, not worry about him getting back onto the pitch."
Jennifer Browne, defending, said Fitzgerald had acted out of "misplaced loyalty" to his girlfriend.
She said: "Quite wrongly he took matters into his own hands after an incident between the injured party and his current girlfriend."
Browne said the influence of alcohol was a contributing factor in the incident, for which Fitzgerald was "totally disappointed in himself".
Fitzgerald was also fined £100 for going on to the pitch, and ordered to pay a £15 victim surcharge.