The 21-year-old Zverev and the 29-year-old Gulbis have never played, but they know each other. Gulbis was a houseguest of the Zverevs during a training trip when he was younger. They also share a common strength: Their two-handers. We often talk up matches that are “showcases for the nearly-extinct one-handed backhand”; this match will showcase the two-hander, and remind us how good it can look, and how useful it can be. As far as who is going to win, that’s a tougher call than it might appear at first. Yes, Zverev is ranked far higher; while he was winning Madrid and reaching the Rome final, Gulbis was playing Challengers in Bordeaux, Prostejov, and Caltanissetta. But Gulbis beat Juan Martin Del Potro here last year, and he qualified for this main draw, so he should be as match-tough as he’s going to get. And Zverev has a habit of letting lower-ranked opponents hang around in best-of-five-set matches. Winner: Gulbis
WATCH—Daily Serve from Day 5 at Wimbledon: