Scott Harrison (right) was not at his best on Saturday

Harrison's father and trainer, Peter, told BBC Scotland that the Glasgow fighter was debilitated by a bug before the second defence of his title at the Braehead Arena.

"We all know Scott can box a lot better than he did on Saturday night," said Harrison senior.

"He was a bit lethargic but he was only fighting at 30 per cent.

Harrison suffers shock defeat

"There has been a bit of illness in the family with his partner Jackie and his son, young Scott, suffering with colds.

"And on Friday, just after the weigh-in, Scott actually vomited twice - which was unknown to myself until after the fight."

Medina won a record fifth world title with a spilt decision over Harrison and the experienced Mexican looked in control throughout the bout.

However, Harrison senior believes it won't be long before his son wins back his belt.

"I was impressed by Medina's movement - he must have run a marathon on Saturday. But he wasn't punching hard.

"Scott is a determined character and he will come back from this defeat stronger and more determined.

"He's only 25 and Scott wants his title back for himself and for all of the boxing fans of Scotland.

"Remember, Marco Antonio Barrera is acknowledged as the best fighter in the world, but he's been knocked out twice. Lennox Lewis has been beaten."

We need to get Medina back in the ring and we need to make sure we get our title back Frank Maloney Scott Harrison's manager

Meanwhile, manager Frank Maloney is confident that Harrison will only have to wait until September for a rematch with Medina.

After Saturday's fight, the Mexican's manager Ignacio Huirez indicated that Harrison would have to wait 10 months for the chance to exact revenge to allow the 32-year-old ample recovery time.

But Maloney is optimistic that the second instalment will go ahead in just two months' time.

"I've already spoken to (promoter) Frank Warren and I've told him that I'd like it to go ahead in September and that's possible. All our talk now is about Medina.

"We need to get Medina back in the ring and we need to make sure we get our title back. We can't talk about anything else at the moment."