Two all-time tennis greats met for what could be the final time on Monday at Roland Garros. Novak Djokovic defeated Rafael Nadal 6-1, 6-4 in the second round of the Olympic men's singles tournament. It was the 60th time Djokovic and Nadal have faced off.  Combined they have an incredible 46 Grand Slam wins in their careers. The 38-year-old Nadal has hinted at retirement as he continues to struggle with injuries. What's your prediction for Nadal?  Will he retire after the Olympics or continue on?