Five matches to watch on the first day of the French Open

Jelena Ostapenko will embark on her first-ever Grand Slam title defence on Sunday

The 2018 French Open gets underway on Sunday, with men's second seed Alexander Zverev and reigning women's champion Jelena Ostapenko among those in action. Here are five matches well worth watching on the first day at Roland Garros: Ostapenko (LAT x5) v Kozlova (UKR) The final match on Philippe Chatrier could be the best of the bunch, with the big-hitting but often erratic Ostapenko opening her title defence against Kateryna Kozlova. The Ukrainian's game is not at the same level as the fifth seed's, but Ostapenko will have to deal with the occasion and returning to Roland Garros as defending champion. It's easy to forget that she is still only 20, and she will have to show experience to control her attacking instincts against the world number 66. Berankis (LTU) v Alexander Zverev (GER x2) Second seed Alexander Zverev is considered by many to be the main threat to Rafael Nadal's hopes of an 11th French Open triumph. The 21-year-old German picked up back-to-back titles in Munich and the Madrid Masters earlier this month, before rounding off an impressive clay-court season with a narrow final defeat by Nadal in Rome. But he is yet to reach the quarter-finals of a Grand Slam tournament, and Ricardas Berankis will be hoping to emulate Fernando Verdasco's first-round win over Zverev in Paris 12 months ago. Benchetrit (FRA) v Monfils (FRA x32) Home favourite Gael Monfils is not the force he was when reaching the semi-finals here 10 years ago, but the French fans will still turn up to watch his exciting style of play. The 31-year-old has slipped down the rankings after a succession of injuries, and has been handed a potentially tricky first-round clash on Suzanne Lenglen against 19-year-old wildcard Elliot Benchetrit, who is ranked just outside the world's top 300. Wang (CHN) v Venus Williams (USA x9) Venus returns to Roland Garros for her 21st appearance, still ranked inside the world's top 10 and seeded ninth. The evergreen 37-year-old faces China's Wang Qiang in the third match on Lenglen. The seven-time Grand Slam champion is looking to reach the French Open quarter-finals for the first time since 2006 after back-to-back last-16 defeats. Venus has won both of her previous matches with Wang, including in the first round at Roland Garros last year. Schiavone (ITA) v Kuzmova (SVK) Italian veteran Francesca Schiavone, the 2010 French Open champion, has already had something of a surprise run in coming through qualifying to make the main draw. The world number 151, who turns 38 later this month, flirted with retirement last season and had lost all of her six previous matches this year. But a crushing 6-0, 6-1 win over Russian Evgeniya Rodina gave her a place in the first round, and her match with 20-year-old Slovakian Viktoria Kuzmova on Court 3 could be an interesting clash of generations.