"He has got a lot of work to do; a lot of work.

"Forget the fitness side of things, because anyone can get that right, it's the touch, it's the taking on players one on one, it's the passing.

"If he's saying four or five months and it's not costing you anything, which it isn't because you have sponsors, I'd have no problems persevering with him.

"If he actually wants to persevere with it for four or five months, fair play to him.''

Such was the interest in Bolt around the globe, Bosnich was interviewed by CNN International about the eight-time Olympic Gold medallist's performance in Gosford.

"If Usain can put his mind to being the fastest man in history over the 100 metres, then he can put his mind to trying to become a professional footballer,'' Bosnich said.

"Whether that will happen in the A-League I don't know and couldn't say with any certainty after 20 minutes in a trial.''

Bolt said after stretching his legs against a local representative team of amateurs he felt the pinch after 15 minutes.

He looked genuinely nervous as he warmed up on the sideline with Mariners' head of performance Andrew Young and would have no doubt burned some of his energy before taking the field in the No.95 jersey, a not-so-subtle ode to his 9.58-second 100 metres world record.

Bolt's was expected to last no more than a month at the Mariners, but coach Mike Mulvey is prepared to give him 12 months. Cynics have the speedster leaving before the A-League kicks off next month.

"In four months’ time I’ll be fit,'' Bolt said. "I’ll be getting a lot more time on the ball, and I personally feel I will get a contract by then.

"I'll be playing much more time. It's about working and taking my time. I think in four months I should be ready and be one of the boys.

"I think the first 15 [minutes] was pretty good, the last five I could feel my back getting a little bit tight. But overall I wasn’t too tired, so that’s a good sign. Its about getting my fitness up.''

Bolt played on the left wing before he shifted to the forward line against a team who defended deep in the second half, denying him the chance to pounce on any long balls.

Mulvey was proud of Bolt's maiden hit-out and said his presence had already lifted the team at training.

Bolt also put bums on seats, although the 9958 fans on Friday night was down on the anticipated crowd of 12,000.

"Wow, have we won something?'' said Mulvey, when he was greeted by plenty of TV cameras at the post-trial press conference.

As for Bolt, Mulvey said it was impossible to assess the Jamaican's talents until he is fully fit. Bolt only touched down in the country two weeks ago.

"He's an honest guy and will tell you that himself,'' Mulvey said in reference to Bolt's fitness. "I'll give him 12 months if required.''