Mischa Zverev saw off the challenge of Mikhail Youzhny in the MercedesCup to earn himself a clash against Roger Federer.
The German secured a 7-6 (7-5), 6-3 victory over Youzhny to set up a second-round match against 20-time Grand Slam winner Federer.
There were no breaks of serve in the first set with Zverev edging the tie-breaker while the crucial break came in game six of the second set.
Teenage wild card Rudolf Molleker also advanced as he became only the second 17-year-old to win a match on the ATP Tour this year as he beat fellow German Jan-Lennard Struff 6-4, 6-7 (5-7), 6-3.
He will face second seed and defending champion Lucas Pouille, who had a bye in the first round, for a place in the quarter-final.
Guido Pella booked his place in the second round as he beat Australian John Millman 6-2, 6-2 while Florian Mayer was a 6-4, 6-1 winner over Yannick Maden.
Sloane Stephens, Karolina Pliskova, Kiki Bertens exit.
Rafael Nadal committed to Davis Cup.
Johnny Nic on why Jamie Murray deserves more praise than brother Andy.
In Tennis Today, Andy Murray surprises four tennis fans.
Jo-Wilfried Tsonga sees off Guido Pella at European Open.
Julia Goerges and Garbine Muguruza safely into second round of Luxembourg Open.
Nick Kyrgios beats Andrey Rublev at Kremlin Cup.
Joe Tyler caught up with rising British tennis star Jake Draper.
Simona Halep has pulled out of the Kremlin Cup.