Roger Federer said he didn't realise how highly Bernard Tomic was ranked when he criticised the Australian earlier this month.
The Swiss great sparked a war of words between the pair when at the Brisbane International he was asked about Tomic's quest to break into the world top 10. 
"He's been struggling to show [it], to be quite honest," Federer said then. "The year is not just one month long or one week long. It's 52 weeks. It's every day. That [is what] he's been struggling to show, to be quite honest.
"Many seasons now in a row we have seen or heard that top 10 is the goal, and he's missed out on it by a long shot."
Tomic this week hit back at Federer, saying the world No. 3's game was nowhere near that of reigning Australian Open champion Novak Djokovic.
"He has his predictions. I think he's also far away from Djokovic as well if he wants to say that.
"If he believes I'm very far away from the top 10, I also believe my prediction that he's nowhere near Novak's tennis right now," Tomic told reporters after setting up a last-16 clash with second seed Andy Murray.
"It also motivates me. I'm working for that. When I'm playing well, I'm a top-eight player in the world."
Federer beat Tomas Berdych in straight sets on Tuesday to advance to the semi-finals of the Open, where he will play either Djokovic or Japan's Kei Nishikori, whereas Tomic was knocked out of the tournament by Murray on Monday night.
Federer said he felt his comments about Tomic had been taken out of context, because he also said some nice things about the 23-year-old Queenslander.
He also admitted he had not realised how highly Tomic was ranked when he said he was a long way from making the top 10.
Australia's other controversial young gun, Nick Kyrgios, was knocked out of the Australian Open by Berdych in the third round.
Federer, now a much-loved figure in world tennis, said he too had felt misunderstood by the public at the start of his career.