Serena Williams hits a forehand in her first-round match at the French Open. Adam Pretty/Getty Images Europe/Getty Images
Williams lost the first set to Vitalia Diatchenko and was left frustrated with some of her errors. Adam Pretty/Getty Images Europe/Getty Images
But helped by her serve, Williams then cruised. She is bidding for a record-tying 24th grand slam title. THOMAS SAMSON/AFP/AFP/Getty Images
Rafael Nadal, the 11-time tournament winner, began his tournament by facing Germany's Yannick Hanfmann. THOMAS SAMSON/AFP/AFP/Getty Images
He slipped at one stage but picked himself up and looked in commanding form in the straight-set victory. Adam Pretty/Getty Images Europe/Getty Images
Nadal will next face another German in the second round, Yannick Maden. Adam Pretty/Getty Images Europe/Getty Images
Novak Djokovic stretched here but wasn't stretched in his opener, looking sharp in dispatching rising Pole Hubert Hurkacz. Adam Pretty/Getty Images Europe/Getty Images
Djokovic is attempting to win four straight majors for the second time in his career. THOMAS SAMSON/AFP/AFP/Getty Images
Injured ahead of the French Open, former No. 1 Caroline Wozniacki fell to Russia's Veronika Kudermetova in three sets. Adam Pretty/Getty Images Europe/Getty Images
And Petra Kvitova, one of the contenders, had to pull out of the event due to a forearm injury. Alex Grimm/Getty Images Europe/Getty Images