When a woman asked her boyfriend to leave her home he refused and knocked her out.
Reece Donovan admitted attacking Trisha Munroe at her address in Station Road, Bristol.
Bristol Crown Court heard that, after regaining consciousness, Ms Munroe awoke with the taste of blood in her mouth and a bruised face.
Donovan, 25, of Melton Crescent in Horfield, pleaded guilty to assault occasioning actual bodily harm on April 12.
Judge James Patrick handed him a 15 months prison sentence suspended for two years.
He told Donovan, who has been remanded in custody since May: "When I read these papers I had no hesitation thinking you would be going back down those stairs for some time.
"You obviously don't understand how you should be treating other people and it is completely unacceptable forcing your will on other people and seeking to manipulate them."
Donovan was told to go on a Building Better Relationships course, carry out 100 hours' unpaid work and abide by a five-year restraining order banning him from contact with Ms Munroe.
Lucy Taylor, prosecuting, said Ms Munroe asked Donovan to leave her home but he refused and struck her.
When she awoke in pain he told her he would say it was her fault and she would be the one arrested, the court heard.
Police arrived on the scene after being alerted by a neighbour.
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When interviewed Donovan claimed he had acted in self-defence.
Ms Munroe made an impact statement in which said she could not have Donovan back in her life, asking: "What if he kills me?"
Dianne Heys, defending, said: "This was his first ever proper relationship.
"He has now accepted responsibility and knows full well what he did was absolutely inappropriate.
"She asked him to leave, he should have just left but he didn't.
"He became angry, he lost his temper and he does accept hitting out at her.
"He has genuine remorse."
