Alexander Bublik knocked Denis Shapovalov out of Madrid to reach the last 16 in the Spanish capital.
Ash Barty beat fellow Roland Garros champion Iga Swiatek to reach the Madrid quarter-finals.
John Isner is into the second round in Madrid after beating Miomir Kecmanovic in straight sets.
Petra Kvitova is into the last 16 in Madrid with a comfortable victory over Angelique Kerber.
Iga Swiatek will meet Ash Barty on Monday in a clash of the Roland Garros champions.
Jil Teichmann stunned Elina Svitolina as Ash Barty and Iga Swiatek cruised through in Madrid.
Novak Djokovic has withdrawn from Madrid as he looks to recover before an intense build-up to Roland Garros.
The Spanish tournament has unveiled a series of new initiatives that will be implemented in this year.