Alexander Zverev defeated Arthur De Greef 6-3 6-3 6-4 in the BEL vs GER round robin on hard.
Zverev A. took it in straight sets.
Alexander Zverev beat Arthur De Greef 6-3 6-3 6-4. Umpiry, "Alexander Zverev vs Arthur De Greef — BEL vs GER Round Robin", https://umpiry.com/match/2017-02-03/greef-vs-zverev-bel-vs-ger-rr?utm_source=cite (as of 3 February 2017).