PARIS, France -- Novak Djokovic was likened to a snake devouring its prey Tuesday as his bid to become the first man in half a century to win all four Grand Slam titles twice got off to a straightforward start at Roland Garros while a 'double bounce' row prompted calls for video replays to be introduced in tennis.
World number one Djokovic, returning to Grand Slam action for the first time since his US Open disqualification, eased past Sweden's Mikael Ymer, ranked 80, in straight sets 6-0, 6-2, 6-3.
It was his 32nd win in 33 matches in 2020 and kept him on course for a second French Open title following his 2016 triumph, and 18th career major.
"It's always a pleasure to return to Paris on Philippe Chatrier, this important court. The atmosphere is a little different this year with few fans but I remain motivated to win the title," said Djokovic, only one of two men to have defeated 12-time champion Rafael Nadal in 15 years in Paris.
The 33-year-old top seed is in the second round for a record-equalling 16th time, matching Guillermo Vilas and Nadal.
Djokovic, who suffered no immediate hangover from his US Open controversy by quickly wrapping up a record 36th Masters title in Rome on the eve of Roland Garros, next faces Lithuania's Ricardas Berankis.
Ymer, making just his fourth main draw appearance at a major, graphically summed up the challenge of facing Djokovic.
"It felt like when a snake kills its prey," said 22-year-old Ymer. "I had chances to rally but then I got suffocated."
Russia's Andrey Rublev, the 13th seed who won the Hamburg title just two days ago, staged a remarkable recovery from two sets and 3-5 down in the third to beat Sam Querrey of the United States 6-7 (5/7), 6-7 (4/7), 7-5, 6-4, 6-3.
"My attitude today was really horrible and it needs to change," said Rublev, who had lost both his previous matches in Paris.
Greek fifth seed Stefanos Tsitsipas, the runner-up in Hamburg, also needed five sets to make the second round, beating Spain's Jaume Munar 4-6, 2-6, 6-1, 6-4, 6-4 on the back of 54 winners.
"I never had a match like this before," said Tsitsipas after coming back from two sets down for the first time in his career.
Kristina Mladenovic called for a football-style VAR system to be introduced in tennis after her opponent profited from a double bounce to help knock the Frenchwoman out of her home Grand Slam.
Mladenovic was 5-1 up and with a set point against Laura Siegemund when the German scooped a winner despite the ball appearing to bounce twice. The incident was missed by chair umpire Eva Asderaki.
World number 44 Mladenovic pleaded in vain before Siegemund took full advantage, racing into the next round with a 7-5, 6-3 win.
- 'Replace human with camera' -
"It would be great to have that," said Mladenovic when asked if video replays should be introduced.
"It'd be a pity to replace a human with a camera but to err is human. I don't see how the umpire could not see it. Unfortunately, she continues at Roland Garros but I do not."
Second seed Karolina Pliskova ended Mayar Sherif's fairytale Grand Slam breakthrough to set up a second round clash against former champion Jelena Ostapenko.
Pliskova, a semi-finalist in 2017, squandered eight set points in the opener as world number 172 Sherif, the first Egyptian woman to play in the main draw at a Slam, took a shock lead.
However, the Czech's greater experience eventually told as she recovered to progress 6-7 (9/11), 6-2, 6-4.
Latvia's Ostapenko, the world 43, won her first match at the French Open since sweeping to her shock 2017 title when she fired 46 winners past Madison Brengle of the United States to win 6-2, 6-1.
- 'Pressure all gone' -
"After I won here it was a tough time. I had to get used to the pressure but now it's all gone," said the 23-year-old Ostapenko.
Denmark's Clara Tauson, just 17 and a qualifier, unleashed 48 winners to knock out American 21st seed and US Open semi-finalist Jennifer Brady 6-4, 3-6, 9-7. Tauson also saved two match points on her way to a maiden career main draw win.
Australian Open champion Sofia Kenin recovered from a break down in the final set to defeat 125th-ranked Russian Liudmila Samsonova 6-4, 3-6, 6-3.
Fourth seed Kenin, who dumped out Serena Williams in Paris a year ago, fought back from 2-0 down in the decider to advance to a second-round tie against Romania's Ana Bogdan.
© Agence France-Presse