Nadal advanced after Marcos Daniel retired during the second set with a knee injury, while Murray got through when Karol Beck succumbed to shoulder trouble while trailing in the third set.
Swedish fourth seed Robin Soderling was untroubled in downing Italy’s Potito Starace in straight sets, while former US Open champion Juan Martin del Potro also made a winning Grand Slam return after missing nearly all of last season with a wrist injury.
Argentine 27th seed David Nalbandian came from behind to overhaul Australian Lleyton Hewitt to win a compelling five-setter, 3-6, 6-4, 3-6, 7-6 (7-1), 9-7 in a 4 hours 48 minutes night match.
Spanish top seed Nadal, bidding for his fourth straight major title to complete a non-calendar year Grand Slam, was leading 6-0, 5-0 when Brazil’s Daniel retired with a painful left knee.
Nadal was only on court for 47 minutes and the nine-time Grand Slam champion sought more work on his service after the injury-shortened match.
