Sydney: Juan Martin del Potro's winning comeback after 10 months out through injury was ended by qualifier Mikhail Kukushkin at the Sydney International on Thursday.


Juan Martin del Potro. Pic/AFP 

The Argentine defending champion, who spent much of last year recovering from wrist surgery, was knocked out in two tiebreaker sets by the Kazakhstan qualifier, 7-6 (7/5), 7-6 (7/3) in just under two hours. Del Potro, who beat Sergiy Stakhovsky and top seed Fabio Fognini to reach the quarter-finals after he was awarded a wildcard into the tournament, fought to the end, but found Kukushkin too strong on the day.