Nadal, who played just seven matches between Wimbledon and the end of 2014 due to injury and appendix surgery, lost in the first round 1-6, 6-3, 6-4.
The Spanish 14-time grand slam winner was using the event as a key part of his preparations for the Australian Open, which is due to start in Melbourne in 12 days’ time.
Women’s world No1 Serena Williams’s form is also a worry, meanwhile, after she was thrashed 6-2, 6-1 in just 50 minutes by Canada’s Genie Bouchard in the Hopman Cup in Perth.
Williams, 33, needed an on-court espresso to get over a sluggish start against Italian Flavia Pennetta on Monday, but was bemused to be able to muster only faint resistance against Bouchard.
“I don’t know what’s wrong with me, I’m so tired,” she said. “Maybe she needed another coffee,” Bouchard quipped.