Alexander Zverev cruised into the quarter-finals of the Geneva Open with a 6-2 6-1 win over Ernests Gulbis, while there was a first-round exit for Grigor Dimitrov.
Dimitrov, who was ranked number four in the world 12 months ago but has now sunk to 47, accepted a wildcard to appear in qualifying for the first time in a tournament since the 2012 Paris Masters in order to reach the main draw.
But that was as far as the Bulgarian got, as Federico Delbonis recovered to earn a 1-6 6-4 6-2 win and move into the last 16.
There were no such problems for top seed Zverev in his match, with Gulbis offering little resistance and going down to defeat in one hour and six minutes.
Gulbis was not without his chances, but Zverev saved eight of the Latvian's nine break-point opportunities and took five of his own to end a two-match losing streak.
"It was a good win, obviously [Gulbis] is someone that plays very aggressive and hits the ball very hard at times," Zverev said.
"In the first few games I thought it was going to be a very difficult match and then I picked up my level a little bit."
Zverev will face Hugo Dellien in the last eight after the Bolivian defeated Janko Tipsarevic in Tuesday's final match.
Other round-of-32 clashes saw Joao Sousa edge a tight encounter against Leonardo Mayer, Albert Ramos-Vinolas get the better of sixth seed Adrian Mannarino and Damir Dzumhur beat Feliciano Lopez.
In the Lyon Open, number four seed Felix Auger-Aliassime defeated John Millman in straight sets, while Steve Johnson knocked out home favourite Pierre-Hugues Herbert.
There was some cause for celebration for the French fans, though, as Benoit Paire and Corentin Moutet booked places in the last 16, as did Uruguayan veteran Pablo Cuevas.