Daniel Altmaier was frustrated by losing his serve to Tommy Paul at a crucial time during their Hamburg Open quarterfinal in Germany.
A whole new set of tennis rules will be tested by the ATP Tour during a new season-ending tournament for the top 21-and-under players in Milan in November.
Laver Cup Day 2: Federer tops Krygios; Nadal splits; Europe leads 7-5 ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results