Dominic Thiem has accused Serena Williams of showing a "bad personality" after his press conference was cut short to allow the American to take over the main interview room at Roland Garros.

Thiem, who reached his first grand slam final here last year, was discussing his third-round win over Pablo Cuevas with German language journalists when he was told he would need to leave the room.

The fourth seed was understandably unhappy, saying: "I don't really get it, seriously. What the hell? But it's a joke, really. What's the point of that, that I have to leave the room because she's coming?"

It's understood that, while Williams did not request for Thiem to be ousted, she was unwilling to wait for the Austrian to finish and the second interview room was also in use, leaving organisers in a difficult position.

The American was not in the best of moods having been beaten by Sofia Kenin in her earliest loss at a grand slam for five years.

Tournament director Guy Forget apologised to Thiem for the incident and, speaking to Eurosport on Sunday, the 25-year-old was in no mood to forgive Williams.

He said: "I wasn't angry or frustrated. Maybe for a couple of minutes or so. It is just the principle.

"It doesn't matter if it is me who sits in there. Even if a junior is in there, every player has to wait.

"It is a matter of course. It also shows a bad personality, in my opinion. I am 100% sure (Roger) Federer or (Rafael) Nadal would never do something like that."

Federer had earlier weighed in on the issue after his fourth-round victory over Leonardo Mayer, saying: "I don't know what went wrong but something went wrong for this to happen.

"I think there is, with all the players, (an understanding) the one who is still in the tournament gets priority.

"If I would have lost today against Mayer, I would let Mayer go first or decide when he wants to go to press as he's got a next match. My next match is far, far away. So that's just the way you go about it.

"There must have been a misunderstanding, or maybe they should have kept Serena still in the locker room, not waiting here in the press centre. I understand Dominic's frustration. For him it's just about how in the world did this happen?"