STUTTGART — Canada's Felix Auger-Aliassime fell 6-4, 7-6 (5) to American Taylor Fritz on Saturday in semifinal action at the Stuttgart Open.

First quarter-final, first Top 50 victory: the 17-year-old German is causing a minor sensation on home grass at the BOSS Open.

A day after Justin Engel became the youngest tennis player in 40 years to reach a men's tour quarterfinal on grass, his run at the Stuttgart Open ended with a loss to Felix Auger-Aliassime on Friday.

With Roland Garros in the rearview, top players on the ATP Tour are shifting their focus to the grass-court season as they prepare for Wimbledon. Alexander Zverev kicked off his campaign at the BOSS Open in Stuttgart on Thursday with a win over Corentin Moutet.