Tunisian Ons Jabeur claimed the biggest scalp of her career at the Western & Southern Open on Monday evening, taking out defending champion Madison Keys in straight sets.

Jabeur hit five aces on her way to a 6-4 6-1 victory, but it was her unforced error count – 17 to Keys’ 29, that played a significant part in the win.

“It was a really good match for me, I had to really play good and I served really good,” Jabeur said.

“I’ve been waiting the whole day to play,”

Then pair didn’t take to court until 9.30pm.

“So I really wanted to not waste anything. I didn’t give her the chance to get her rhythm back. I know it was very difficult as a first match for her – luckily I played before in Lexington.

“To be honest, I’m very, very proud of the way I played today.”

Jabeur will play qualifier Christina McHale in the third round.

McHale beat Ekaterina Alexandrova 6-1, 7-6(8) earlier in the day.