The 22-year-old utility missed out on selection for the final Socceroos World Cup squad due to a pelvic injury which he has been receiving treatment on in Australia for the past three months.

Williams has been working with highly-regarded physiotherapist Anthony Hogan in Australia but is due back at Middlesbrough training this Monday.

And the Perth-born youngster told mfc.co.uk he wants to turn his World Cup frustration into a positive in the long-term.

"In the long run I think it may have been a blessing in that I'm even hungrier and more driven to help my country get to the next one and hopefully have a more influential role," Williams said.

"It was heartbreaking to tell the truth, to miss out on what is the biggest tournament in anyone's life was really hard to take at first.

"Saying that, if I did go with my health and fitness not at 100 percent, I really feel I couldn't perform to my maximum and really didn't want to let myself and both the managers down."

Williams was one of the final Socceroos to miss the cut for Pim Verbeek's final 23-man squad and revealed how it went down in South Africa.

"It was after the Denmark friendly in South Africa that the manager spoke to me," he said. "He more or less asked how I was feeling and why all my training stats were well off where I should be.

"I just said I was really struggling with my injury and I was down in the dumps because I was watching my team-mates train everyday while I was receiving treatment.

"The manager said he was going to leave me out of the 23 but asked me to stay just in case an injury came along but I said I wanted to go home and try to get the World Cup off my mind, as being in South Africa would have made me a thousand times more frustrated in myself.

"I came back to Perth and the following day jetted out to Bali with my girlfriend and siblings just to try get my mind off what I was missing out on."

Williams added his rehabilitation has been coming along under Hogan's guidance, but there was still plenty of work ahead.

"My groin and pelvis are getting a lot better but we are not quite into running or ball work yet," he said.

"The time I've had here has also made me concentrate on strengthening my lower and upper body, which I feel a lot stronger and better for, as my thin frame may be to blame for this injury.

"We've been working long and hard on my core stability and strength, we work every day and I have the weekend off to recover and get ready for the next week.

"Our main aim is to strengthen my mid-section and make it strong enough to see off any more problems with my groin. We also do upper and lower body weights three times a week to make me a stronger and better player."

The Socceroo, though, was reluctant to place expectations on when he'll be back playing.

"It's tough to put a timeline on things because this injury has a mind of its own," he said. "One morning I could wake up and everything could be fine and yet again it might not want to settle for a while.

"I don't really want to set a timeline and let people down if I'm not ready by then, but also I could be ready soon.

"It's really hard to say right now and I just concentrate on recovering and get stronger so I can come back and be a better player all round."

He added: "The worst thing for footballers is injuries and yes, of course frustration kicks in a lot.

"When things are going bad or when things are looking really good it makes no difference to the frustration, as I just want to be on the pitch again playing for the fans and the manager."