In Nice , Thiem successfully defended his title , beating Alexander Zverev , having not lost a set until the final .
In the quarterfinals , Thiem lost to sixth seed Kei Nishikori in straight sets .
In Nice , Thiem successfully defended Thiem 's title , beating Alexander Zverev , having not lost a set until the final .
In the quarterfinals , Thiem lost to sixth seed Kei Nishikori in straight sets .