Sofia Kenin says she is very comfortable with her bizarre, no-look service action which has carried her into a maiden Roland Garros final.
The 21-year-old American has developed the habit of throwing the ball in the air while simultaneously staring down at her feet.
Only when the ball is at its high point and her racquet is in motion does she then swivel her head back up.
"I've had that my whole career. I know it's a little bit different. I've had great success with it. I think it would be quite wrong to start changing things now," said Kenin.
On Saturday, she faces Iga Swiatek of Poland where she will attempt to add the Roland Garros title to the Australian Open she won earlier this year.
"I've improved my serve. I feel like I'm serving well. I guess maybe it doesn't matter how you serve, as long as you get it in. Yeah, that's worked for me," she added.