Defending champion Novak Djokovic made a winning French Open start under new coach Andre Agassi, cruising past Spain's Marcel Granollers 6-3 6-4 6-2 in the first round. He will next take on Joao Sousa of Portugal in the second round.
The Serb's campaign began in similarly ominous fashion as he took just under two-and-a-half hours to win 6-3, 6-4, 6-2 on the showpiece court, Philippe Chatrier, against Nadal's compatriot Marcel Granollers, ranked 77.
"I'm very happy to be back here after what happened a year ago. He's an uncomfortable opponent that already had some good victories this year", said Nadal. "I'm patient, and for us this is a great way to start our collaboration and friendship and get to know each other and then see where it takes us".
Kyrgios, notorious for his periodic bad temper and sulks on court, sealed his victory on his first match point. "After that I made the break straight and then finished a close set, then it was a little bit less hard", he added.
Nadal dominated the opening set, then recovered from a slight second-set wobble when he dropped serve twice in a row to surge into the second round, where he will meet Dutchman Robin Haase.
"I pulled my back yesterday and specialists were saying I needed 48 hours, I was nearly sure I could not take it to court today", said Mladenovic, who burst into tears after a two-hour-59-minute tussle.
Although Muguruza's first-strike tennis proved too much for the 36-year-old Italian as she beat her 6-2, 6-4, the Spaniard was full of admiration afterwards.
Schiavone, the 2010 champion, showed her usual fighting spirit and saved three match points before sending a forehand volley wide.
Should he achieve his dream of a "decima" the 30-year-old would become the first man to win 10 titles at any single grand slam event. When I look back on some videos, I heard her name.
Muguruza's victory was an emphatic one and the manner in which she overcame a former champion was impressive however her performance certainly was not flawless. "I think she has moments where she's unbelievable".
Schiavone again responded but Muguruza broke to lead 5-4 and came through a long final game to set up another tricky match against Estonia's Anett Kontaveit, one of the form players of the clay season.
Frenchman Gilles Simon was another seed to go out after a 1-6 6-2 6-4 6-1 defeat to Nikoloz Basilashvili of Georgia, while 32-seed Mischa Zverev of Germany crahed out at the hands of Italy's Stefano Napolitano 4-6 7-5 6-2 6-2.