Novak Djokovic (SRB)  vs Alexander Zverev (GER) . Djokovic has yet to lose a set at this year's tournament and now has an amazing 25 match winning streak at Grand Slams as he goes for his second career "Nole Slam." He is going for his thirty-fifth major semifinal, while his opponent is going for his first. Interestingly, Zverev has an even head-to-head from the four matches the two have played, which is notable because while there are only 80 players who have played at least 4 matches with Djokovic only one person has a winning record (Andy Roddick!) If Zverev does win the match tomorrow, he would be in rarefied company. But I don't think that's going to happen. Mad Professah's pick: Djokovic.
Roger Federer (SUI)  vs
Rafael Nadal (ESP)  vs Kei Nishikori (JPN) . Two of Nishikori's four matches here have been 5 sets while Nadal has only dropped a single set in 4 matches, with numerous breadsticks and bagels handed out. Nishikori has 2 wins (compared to 10 losses) against Nadal, but neither of the wins have been on clay or in 5 sets. Nadal's record at Roland Garros is 90-2. It doesn't seem likely that one of these very historic results will happen against Nishikori. Mad Professah's pick: Nadal.