"I felt like anything I did, I wasn't quite sure how to respond," Tomic said. "I wasn't quite comfortable, I think, the whole match on that court. It was very strange.
"It was a good experience to play on that court. I had to get confronted on that court sooner or later."
Officials accepted Tomic's version of events, with a spokesman saying that the ITF "looked into the match like it looks at every match but no action will be taken" against the Australian.
McEnroe, commentating for ESPN, said Tomic had "concentration problems" and would "continue to struggle" until he learned to focus on every point.
"Tomic is teeing it up. It looks like the tank job," he said.
"This is a shame. You don't like to see this. I like to see Andy win but, other than that, it's poor."
McEnroe's younger brother Patrick, a former US Davis Cup captain, was even more scathing.
"Pathetic," he tweeted. "In case you were wondering I was referring to [the] effort from Tomic."
Officials have the capacity to fine players for not giving 100 per cent effort.
Roddick said Tomic - who followed up his singles defeat with a second-round doubles loss yesterday with Matthew Ebden - needed to take the good with the bad.
"If I had one piece of advice," Roddick said, "I would tell him it's probably never as good as it seems at a given moment, and it's probably never as bad as it seems at a given moment as well."
- AAP