Rafael Nadal: how much longer can king of clay reign?
The best clay-court player of all time aims to complete a 10th year of domination, having won his first French Open in 2005. In 60 matches at Roland Garros Nadal has lost only once, to Robin Soderling in 2009, when his knees were shot. The only man to have won the same Grand Slam singles trophy eight times is just 27. Only more knee trouble looks likely to stop him adding to his 43 clay-court titles in the coming weeks.
Novak Djokovic: this could just be his year in Paris
Two years ago Djokovic was gaining the upper hand on Nadal in the French Open final when rain came to the Spaniard's rescue. Last year, having ended Nadal's run of eight successive Monte Carlo titles, Djokovic led his great rival 4-3 with a break in the fifth set of their Roland Garros semi-final, only to lose it 9-7. If anyone can stop the world No 1 it is surely Djokovic, who has won their last three meetings, albeit on hard courts.
Stan Wawrinka: looking to rediscover Melbourne magic
Since breaking into the elite group of Grand Slam champions with his victory over Rafael Nadal in the Australian Open final in January, Wawrinka has failed to reach the quarter-finals in his two subsequent tournaments and earlier this month lost to Kazakhstan's Andrey Golubev in the Davis Cup. However, he reached his only two Masters Series finals on clay (Rome 2008 and Madrid 2013) and regards it as his favourite surface.
Roger Federer: a final opportunity for glory?
The greatest player in history has won only one Grand Slam (Wimbledon 2012) in four years but, after beating back problems and finding a new lease of life working with Stefan Edberg, Federer believes there is more glory to come. Having originally decided to train during the early part of the clay season, he made a late decision to take a wild card into this week's Monte Carlo Masters. Grass, nevertheless, will probably offer better chances than clay.
Andy Murray: a chance to make up lost ground
The world's top six are all in Monte Carlo this week, but the world No 8 will not play his first clay-court tournament until Madrid next month. Last year's clay-court season was a non-event for Murray, who suffered a back injury that forced him to miss Roland Garros and required surgery in September. He finds clay challenging but reached the French Open semi-finals in 2011. Ivan Lendl, his former coach, says he can win in Paris.
Fabio Fognini: time to shine on the biggest stages
Judged by his stunning victory over Murray in the Davis Cup, Fognini is an outrageous clay-court talent. Judged by his record at Roland Garros, where he has never reached the quarter-finals, he is a shrinking violet on the biggest stages. Nevertheless, three clay-court titles in the last year and a rise to No 13 in the world rankings suggest that the 26-year-old Italian could make his major breakthrough.
Serena Williams: the fight to remain No 1
Williams ended an 11-year wait to win her second French Open title last summer during a year in which five of her 11 titles were won on clay. However, it has not always been her best surface – between 2004 and 2011 she won only one clay-court title – and she has not started the current campaign well, losing first time out to world No 78 Jana Cepelova in defence of her Charleston crown. More such losses and her lead at the top of the rankings will shrink.
Li Na: proving that age is no barrier to success
Winning the 2011 French Open was Li's big breakthrough. The world No 2 has subsequently joined forces with Carlos Rodriguez, who was Justine Henin's coach when the Belgian won her four Roland Garros titles. Like a fine wine, Li is maturing with age. The 32-year-old Chinese, who is only five months younger than Williams, won her second Grand Slam title at the Australian Open in January and has since reached the semi-finals at Indian Wells and the final in Miami.
Maria Sharapova: time to end a 12-month drought
Given her continuing injury worries and blossoming business career, it is a credit to Sharapova's dedication that she carries on playing. The 26-year-old Russian has not won a title for a year and, after suffering more shoulder problems has slipped to No 9 in the world rankings, having been No 2 at this stage last year. She once described herself as "a cow on ice" on clay but won the 2012 French Open and reached last year's final.
Victoria Azarenka: aiming to end slide down the rankings
Another former world No 1 struggling with injury, Azarenka damaged her left foot in Australia at the start of the year. She has played only once since January, losing first time out at Indian Wells, where she feared she might have returned too quickly. Having topped the world rankings 14 months ago, the 24-year-old from Belarus is already down to No 4 and in danger of falling further. Of her 17 titles, only one has been won on clay (Marbella 2011).