[13] Jo-Wilfried Tsonga (FRA) vs. [2] Novak Djokovic (SRB)
[18] Ernests Gulbis (LAT) vs. [4] Roger Federer (SUI)
[6] Tomas Berdych (CZE) vs. [
10] John Isner (USA) [8] Milos Raonic (CAN) vs.
Marcel Granollers (ESP)At this stage, any player can be upset.

I'm going to go out on a limb and give Gulbis the nod. Federer has looked good on serve, but his ground game has not been so good. If Federer's serve falters due to pressure on his ground game, then Gulbis has a shot. But he has to do well and not suffer any of his infamous implosions, so this is certainly not a big chance, but it's there. Let's see how interested Federer is in going further at Roland Garros, which has been said not to be a priority, or packing his grass bags for Halle and Wimbledon.
I'd like to see Tsonga overcome the pressure at his home slam and get the win over Djokovic after that sad loss he had a couple of years ago to him, when he really should have won it. But I don't know. Tsonga has only just recently started playing much better. I'm not sure he can contend with Novak over 5 sets. I think his biggest chance is to blitz Nole in 3 sets. The longer it goes, the worse for Tsonga.
Raonic keeps exceeding my expectations. Granollers has been playing well. He has a shot on clay.
Berdych hasn't lost to Isner on clay in their two meetings on the surface, and I don't think John's high bouncing second serve will bother the tall Czech player. I think Isner's best chance is to use his big wing span and go for the net. But he just doesn't do it enough to make me confident that he can succeed, and one can never be sure about Isner's fitness, especially as the rounds wear on in a major. But you never know. If Isner gets hot on serve, he can be damn difficult to break, and if you can't break, you can't win. So I still have to give him a chance for a minor upset.
Respectfully,
masterclass