Former US Open champion Juan Martin del Potro's comeback from a lengthy injury layoff was cut short by Kazakhstan qualifier Mikhail Kukushkin in the quarter-finals of the Sydney international on Thursday.
The towering Argentine was out for 10 months after having surgery to fix an issue with his left wrist and went down 7-6(5), 7-6(3) to Kukushkin, ranked 66th in the world.
Defending champion Del Potro, who won the US Open in 2009, has seen his ranking plummet to 338 and had hoped to get some match practice in Sydney before the Australian Open begins in Melbourne from Monday.
There was not much to choose between the two players, who went unbroken throughout the match, barring a few points in the tiebreakers.
Australian Casey Dellacqua's progress before her home open was also halted after the top seed bowed out of the Hobart International with a second-round loss to Italian Karin Knapp.
The world number 29, however, did not seem too worried with her 7-5 2-6 6-3 defeat.
"I feel ready for the Australian Open and I feel that I'm the best prepared that I can be and that I have done everything that I possibly can," Dellacqua, Australia's best hope at the year's first grand slam behind Samantha Stosur, told reporters.
"Now I just turn my focus onto the Australian Open and doing what I can in the next couple of days to prepare best for that."
Image: Juan Martin Del Potro of Argentina plays a forehand
Photograph: Scott Barbour/Getty Images
