Bernard Tomic hit back at Australian coach Roger Rasheed after his second-round exit at the French Open.
The 20th seed suffered a 3-6 6-2 7-6 (7-4) 7-6 (8-6) loss to Croatian Borna Coric at Roland Garros on Thursday.
Tomic had beaten the returning Brian Baker in the opening round, to go beyond the first hurdle at the year's second grand slam for just the third time.
Rasheed said he "would beat" Baker, who has battled injuries throughout his career and dropped to 635th in the world rankings.
Tomic was unimpressed by Rasheed's comments and said it indicated a lack of knowledge.
"That just shows you how much he knows," he said.
"You don't say that about someone. The guy [Baker] has been to a third or fourth round here, fourth round at Wimbledon , finals of Nice .
"You can't say that about that sort of player. He's beaten Gael [Monfils] on clay and a lot of good players.
"For him to say that comment, just shows you how much education he has."