Former French Open champion Juan Carlos Ferrero reached the second round of the Australian Open on Monday when his ailing Czech opponent Jan Hajek retired.

Spaniard Ferrero, the 24th seed, was leading 3-0 when the Czech threw in the towel complaining of a stomach bug.

Hajek was the second player to withdraw less than 35 minutes after the season's opening grand slam got underway after Joachim Johansson also pulled out of his match against Spain's Gullermo Garcia Lopez.

The reason for the Swede's withdrawal was not yet known. The players were level at 1-1 in the first set.