Jo-Wilfried Tsonga was unable to pull off a third consecutive win over Roger Federer as the top seed reached the last eight in Halle.
Felix Auger-Aliassime will battle with compatriot Milos Raonic for a place in the final of the Stuttgart Open.
Making his grass-court debut on the ATP Tour, Canadian teenager Felix Auger-Aliassime was far too good for Ernests Gulbis.
A pair of seeds exited at the Geneva Open on Monday, while Grigor Dimitrov's match with Federico Delbonis was postponed.
Roger Federer looked very much at home back on clay in Madrid, while Novak Djokovic was a cut above Taylor Fritz.
Roger Federer hardly put a foot wrong in his long-awaited comeback on clay, not facing a single break point against Richard Gasquet.
The 'Next Gen' are making a move at the Australian Open, with 10 men aged 22 or under reaching the third round.
Denis Shapovalov was edged out by Richard Gasquet in Paris on Monday, while Kyle Edmund's season was ended by injury.
It was joy for Ernests Gulbis but despair for John Isner in the Stockholm Open semi-finals.
Top seed John Isner needed almost three hours to overcome Tennys Sandgren and reach the Stockholm Open semi-finals.