French Open semi-finalist Casper Ruud has refuted Holger Rune's claim he yelled in his face after winning the duo's feisty quarter-final clash, accusing the teenager of telling "a big lie".

Ruud beat Rune 6-1 4-6 7-5 (7-2) 6-3 on Wednesday to set up a final-four clash with the resurgent Marin Cilic, scheduled for Friday.

After his defeat, Rune told Danish newspaper Ekstra Bladet that his opponent had shouted at him.

"The team is really nice and sweet, but then he [Ruud] goes straight to me and shouts 'Ja!' straight up in my face," he said.

Rune also accused Ruud of showing "a lack of class", moving the Norwegian to respond in an interview with Eurosport.

Ruud, who is enjoying the best grand slam campaign of his career, has accused Rune of lying in the aftermath of the contest, although he acknowledged emotions were running high at the end of their three-hour encounter.

"No, what he says is wrong," Ruud said. "What he says is really not what happened. We both were in the dressing room after the match, and it's obviously a huge dressing room. There are many players, so we were just in our own part of the room all the time.

"I took an ice bath, ate some pizza and listened to music before we went home. Holger sat in his part of the dressing room.

"How he creates the story of me shouting 'yes' straight into his face is just a lie. It never happened. It's a big lie. It's disappointing that he creates lies about me.

"For me it doesn't matter if he thinks I am a player who doesn't follow the fair play rules, that's not really what matters.

"That's his personal opinion, but to put out lies about me like this is not right. I really wish this is the last time he will do something like this.

"I understand that some players are more emotional than others, and I am as well sometimes. He is obviously someone who plays with many emotions involved.

"I am not surprised about that, but it's a shame that he comes up with all these lies against me and my family."