How unpredictable is the Madrid Open? Noted clay-courter Petra Kvitova won it twice. Rafael Nadal has won the clay iteration of this tournament only four times in its previous nine years since it switched from an autumn indoor hardcourt identity in 2009.

On Thursday, Madrid remained true to form by spitting out a lot of results which don't commonly occur on the tour:

Kyle Edmund made a Masters quarterfinal.

Denis Shapovalov made a clay Masters quarterfinal.

Kevin Anderson made a clay Masters quarterfinal.

Dusan Lajovic made a Masters quarterfinal.

Karolina Pliskova convincingly defeated Simona Halep. 

The reality of Maria Sharapova losing is not that surprising, but given her improving form and the fact that she won the first set on Thursday, her loss to Kiki Bertens might have caught some observers off guard. 

The reality of Juan Martin del Potro losing on clay is hardly staggering... but losing after being up 4-0 in a third-set tiebreaker to a man who -- entering this tournament -- had not won a main-draw match at a clay-court Masters 1000 event, and is almost 28 years old?

That is certainly surprising.

I'm not going to tell you how much of an indicator Madrid is in this column. What I am going to do is share with you the quarterfinalists, WTA and ATP, at the last three Madrid Opens. You can see how neatly -- or erratically -- this tournament sets the stage for the French Open and/or the rest of a tennis season:

2017 WTA Quarterfinalists:

Eugenie Bouchard

Svetlana Kuznetsova

Sorana Cirstea

Kristina Mladenovic

Simona Halep

CoCo Vandeweghe

Kiki Bertens

Anastasija Sevastova

2017 ATP Quarterfinalists:

Borna Coric

Dominic Thiem

Pablo Cuevas

Alexander Zverev

David Goffin

Rafael Nadal

Kei Nishikori

Novak Djokovic

2016 WTA QF-ists:

Dominika Cibulkova


Louisa Chirico

Daria Gavrilova


Irina-Camelia Begu

Samantha Stosur

Patricia Maria Tig

2016 ATP QF-ists:


Milos Raonic

Nick Kyrgios



Joao Sousa

Tomas Berdych

Andy Murray

2015 WTA QF-ists:

Serena Williams

Carla Suarez Navarro

Petra Kvitova


Caroline Wozniacki

Maria Sharapova


Lucie Safarova

2015 ATP QF-ists:

John Isner



Grigor Dimitrov

David Ferrer