Rian Stephen Minnis, 29, is on trial in the ACT Supreme Court over the alleged attack early one morning in December 2013.

He has pleaded not guilty to charges of assault, entering a property without consent and threatening to cause harm.

The court heard Minnis knew the couple well as he had lived across the road for many years and often visited the house.

Minnis had argued with the man over a pair of shoes the day before the incident, prosecutors said.

The Crown alleges the defendant attacked the pair with a baseball bat after he and an unidentified co-offender broke into the woman's home about 4am.

They found the couple and a young child asleep on a lounge in the living room with the television still on.

The woman awoke to a burning sensation in her leg and saw a man, who she recognised as Minnis, standing over her as he wielded a baseball bat.

A second man, who she did not recognise, was armed with a steel bar.

She said Minnis began to beat her partner.

The woman watched the man stand up and then fall to the ground as Minnis continued to strike him, the court heard.

The woman saw a spray of blood come from her partner's head and alleges he left a trail of blood droplets on the ground after he managed to break free from the accused and run to the back of the house.

The offenders fled and the pair called police.

In his opening address, Crown prosecutor Mark Fernandez said there was no dispute over whether the two men entered the unit and inflicted the injuries.

He said it was ''essentially a recognition case'' which revolved around whether the jury could be satisfied Minnis was one of the offenders.

He said the living room where the attack took place was small and had been lit by the television and a lamp which had also been left on.

Defence barrister James Lawton agreed the case hinged on the identification of the attacker, and whether or not it was Minnis.

The trial continues before Justice Helen Murrell on Tuesday.