text: Fourth seed Muguruza went into the match having won only three times on clay this season, but she cruised through the first set.
  Italian Schiavone, 36, won three games in a row to lead the second set but Muguruza fought back to win.
  Muguruza will face Estonia's Anett Kontaveit in the second round.
  "I cannot believe in the first round we have two ex-champions. Not only that but Francesca is a legend and I was very excited to play on Philippe Chatrier court with her," said Muguruza.
  Muguruza defeated Serena Williams to win her maiden Grand Slam title a year ago, but the 23-year-old needs to return to the final to stay in the world's top 10.
  "I know I played good here before, but that doesn't make me extra confident this year. I have to play well to earn that confidence again," she said.
  Schiavone, who is 37 in June, played in the tournament for the final time before her retirement at the end of the year.
  Caroline Wozniacki had to fight hard to beat Australian Jaimee Fourlis 6-4 3-6 6-2.
  Wildcard Fourlis, aged 17 and at 337 the lowest-ranked player in the main draw, pushed the 11th seeded Dane in the second set.
  But Wozniacki, who had to retire during last week's Strasbourg tournament because of a lower-back injury, regained control in the deciding set.
target: Spain's Garbine Muguruza started the defence of her French Open title by beating 2010 champion Francesca Schiavone 6-2 6-4.