RIO DE JANEIRO - American tennis star Madison Keys is so mad for the Olympics she wants to keep playing in the Games till she is a senior citizen. "It's unbelievable. If I could play in 12 Olympics, I'd play in 12 Olympics. Is there senior Olympics for tennis? There should be," said the bubbly 21-year-old. Seventh seed Keys made the third round on Monday with a gruelling three-hour, 7-5, 6-7 (4/7), 7-6 (7/5) victory over Kristina Mladenovic of France. And the Olympic debutant is full of admiration for the athletes who relentlessly train for the chance to shine just once every four years. "It's been great. For us it's a little bit different, we have big events four times a year every year", she added. But you see these people who have trained for four years for this moment and that for me is so special and so great and so stressful, I don't know how to handle it." Keys, who goes on to face Spain's Carla Suarez Navarro for a spot in the quarter-finals, insists she is a fan of the whole Olympic narrative.