Iga Swiatek may hold the top WTA ranking. But the 21-year-old admits she still goes weak at the knees in the presence of Serena Williams.

The American tennis icon is set to retire sometime after the US Open which begins on Monday.

And top seed Swiatek easily admits that she’s a fan of the 40-year-old with 23 Grand Slam singles titles..

“It’s still pretty surreal when I see her. I still feel like I’m just a kid who’s watching,” the 21-year-old said.

“I’ve watched her my whole life. She was everywhere because she always won and was somewhere in the semi-finals or the finals.

“She always seemed really stronger than any of her opponents physically.”

Though she and the veteran have never played, Swiatek said there is plenty to learn as a No. 1 player from the Williams game.

“Mentally she’s the one who’s going to show you how to use your position and how to intimidate with being No. 1. 

“I’m trying to do that. I don’t know if it’s going well or not. We’ll probably see in a couple of months, maybe next season.

The Pole called Williams “the great example, especially with how she copes with (running a) business and playing at the same time or being a mother and playing at the same time.

“It’s just amazing. It’s not like many athletes have done that. It’s great to have somebody like that in our sport who cleared the path and showed us that you can do anything. The sky’s the limit.”