Djokovic, Sharapova shine as Nishikori crashes in Paris
Serbia's Novak Djokovic serves to Portugal's Joao Sousa during their French Open first round match at the Roland Garros stadium in Paris on May 26, 2014 - by Miguel Medina
Second seed Djokovic, the 2012 runner-up who is seeking a first Roland Garros title to complete a career Grand Slam, brushed aside Portugal's Joao Sousa, the world 42, in straight sets, 6-1, 6-2, 6-4.
During a match interrupted by rain, the 27-year-old Serb was at his charismatic best, delighting the Philippe Chatrier crowd by sharing a drink with a ballboy as they sheltered beneath an umbrella.
Djokovic, widely regarded as the favourite to dethrone eight-time champion Rafael Nadal having beaten the Spaniard in Rome two weeks ago, next faces French hope Jeremy Chardy.
Sharapova, seeded seven and the 2012 champion, needed just over an hour to beat fellow Russian, Ksenia Pervak, the world's 156th-ranked player, 6-1, 6-2.
The 27-year-old, who lost last year's final to Serena Williams, looked comfortable under the cloudy conditions on Chatrier, breaking her opponent five times.
Sharapova will next face Bulgaria's 2010 Wimbledon semi-finalist Tsvetana Pironkova.
"First matches at Grand Slams are always tough, no matter how prepared you are, no matter how many matches you've played," said Sharapova, now 13-1 on clay in 2014 with titles in Stuttgart and Madrid.
"There is always a bit more tension in that type of Grand Slam atmosphere. It's certainly more special, especially when you walk out on court."
Nishikori was left feeling as miserable as the Paris weather, clearly still suffering from his recent back injury.
Nishikori, 24, and coached by 1989 champion Michael Chang, was the first Japanese man in 75 years to make the fourth round in Paris in 2013.
But on Monday, there was never any sign that he would repeat that feat as he went down 7-6 (7/4), 6-1, 6-2 to Slovakia's Martin Klizan.
Nishikori won the Barcelona claycourt title last month but then had to quit the Madrid Masters final against Nadal with a back injury that also forced him out of the Rome Masters.
The world number 10 looked distinctly half-fit on Court 1 where he was broken 10 times, hit 10 double faults and committed 40 unforced errors
Left-handed Klizan, 24, one of six former junior champions in the main draw, goes on to face Robin Haase of the Netherlands.
"It sucks," said Nishikori.
- Rain brings problems -
After rain delayed the start of Monday's programme by more than an hour, play was halted again barely two hours later at 1230GMT for a further hour and a quarter.
Seven matches on the schedule were cancelled until Tuesday.
But there was still time for Dominika Cibulkova, the Slovak ninth seed, to beat France's Virginie Razzano 7-5, 6-0 and Italian 12th seed Flavia Pennetta to see off Austria's Patricia Mayr 6-2, 6-2.
German 16th seed Sabine Lisicki, last year's Wimbledon runner-up and who is coached by former world number one Martina Hingis, defeated French wildcard Fiona Ferro 6-1, 7-5.
Also going through was Austria's Tamira Paszek whose 6-2, 7-6 (7/5) win over Belgium's Alison van Uytvanck was her first at Roland Garros for seven years.
Defending champion Nadal remained at the centre of a scheduling row.
Nadal, who has a phenomenal record of 59 match wins and just one loss in Paris, had his opening match against US wildcard Robby Ginepri, the world number 279, shifted out to Suzanne Lenglen court.
The world number one claimed at the weekend that he found conditions on Chatrier to be different this year.
"I think they made the court new, so it's like the clay gets a little bit more fixed. It was moving around a little bit too much and some small stones make the movement a little bit more difficult," said Nadal.
However, his complaints stunned ground staff at Roland Garros.
"I was surprised because nobody else had complained about Chatrier," Gerard Tiquet, the man in charge of the courts for 22 years, told L'Equipe newspaper.
Nadal should have few problems against Ginepri, a US Open semi-finalist in 2005, who has yet to win a match on the main tour in 2014.
Third seed and Australian Open champion Stan Wawrinka, who achieved his best result in Paris in 2013 when he made the quarter-finals, tackles Spain's Guillermo Garcia-Lopez later Monday.