Elise Mertens knocked out two-time Madrid Open champion Simona Halep in the third round in the Spanish capital.

Third seed Halep won the title at the Caja Magica in 2016 and 2017 and was a finalist again the last time the tournament was held in 2019 but she was eventually worn down by the dogged defence of Mertens.

The Belgian was a set down and appeared to be on the back foot in both the second and third sets but eventually battled to a 4-6 7-5 7-5 victory after two hours and 34 minutes.

Halep said: “She played really well, and she definitely deserved to win because she was stronger in the end. I cannot say I played bad, but I did some mistakes, important mistakes. Sometimes it’s just a little bit and the match is going away.”

In the quarter-finals, Mertens will play fifth seed Aryna Sabalenka, who eased to a 6-1 6-2 victory over Jessica Pegula.

Russia’s Anastasia Pavlyuchenko will face Karolina Muchova in the last eight after beating 11th seed Jennifer Brady 7-5 6-7 (8) 6-3.

The Czech earned her place with a hard-fought 6-0 6-7 (9) 7-5 win over Maria Sakkari.

Meanwhile, former Wimbledon semi-finalist and doubles champion Barbora Strycova has announced her retirement.

The Czech, who reached the last four at the All England Club in 2019 and won the women’s doubles title with Hsieh Su-wei, is pregnant with her first child.

Strycova wrote on social media: “Some moments in life just can’t be planned and I am super excited for my next life role as a mom. It doesn’t mean that I will accept that fact that I didn’t play my last match in front of an audience. Once it’s possible, I will play one last match…in front of you. To say proper goodbye.”

The 35-year-old’s last appearance was at the Australian Open in February, where she lost in the first round of the singles and the second round of the doubles.