on his troublesome shoulder in a bid to get himself fit for next month's US Open.

Rafter, who reached the Wimbledon final last month, was knocked out in the quarter-finals of the Masters-Series Toronto event by Jiri Novak on Friday.

And afterwards he withdrew from this week's tournament in Cincinnati, explaining that the shoulder injury which sidelined him for four months after last year's US Open, was once more causing him pain.

An ailing shoulder meant that Rafter's serve was working at less than full pace, and the frustrated Australian appeared to be resigned to defeat after being overwhelmed in the tiebreak and dropping his serve to go down 2-1 in the third set aginst the Czech Novak.

"The problem I learned from the last shoulder problem was that if it's not getting any better while I'm playing it's time to take time off and get it while it's early,'' said Rafter.

"If you keep pushing through it then it escalates into a bigger problem, and that's something I want to avoid. I'll take it a week at a time and I won't be back until it's right.'' Rafter won the US Open in 1997 and 1998, but he withdrew from last year's event during the fifth set of his opening round match against Cedric Pioline with his shoulder in pain. The torn rotator cuff also forced him to miss Australia's Davis Cup triumph last year.

This year, Rafter has helped Australia reach the final again, against Spain in December.

Patrick Rafter: heading back to Bermuda.