June 2 (UPI) -- Novak Djokovic, Rafael Nadal and Ash Barty were among the top players to win their first-round matches at the French Open in Paris Tuesday, but men's No. 7 Andrey Rublev was bounced out of tennis' second Grand Slam event of the year.
German Jan-Lennard Struff defeated Rublev in five sets and needed 3 hours and 46 minutes to upset the Russian. Struff fired 25 aces and converted 91 of 181 first-serve opportunities in the 6-3, 7-6 (6), 4-6, 3-6, 6-4 victory. Rublev totaled 13 aces and won four of 13 break point opportunities.
Struff moves on to face Argentine Facundo Bagnis in the second round Thursday at Roland Garros. Rublev is the second-highest seeded men's player to exit the tournament, after No. 4 Dominic Thiem lost earlier this week.
Djokovic, the No. 1 player in the ATP rankings, needed just an hour and 58 minutes to dispatch American Tenny Sandgren in his first-round match. The Serbian fired four aces, converted five of 11 break points and tallied 33 winners in the 6-2, 6-4, 6-2 win.
"I'm just finding my groove on the court and striking the ball well," Djokovic told reporters. "I'm very pleased with the way I'm feeling and playing on the court. I'm going to try and keep that up. It's a long tournament, but I'll take it match by match.
"Physically, I'm fit, and I'm as motivated as anybody."
Djokovic battles Uruguayan Pablo Cuevas in the second round Thursday.
Nadal, who holds a record 13 French Open titles, won his first-round match in straight sets over Australian Alexei Popyrin. The Spaniard fired seven aces and committed just 23 unforced errors in the 2 hour, 23-minute match. Popyrin converted just one of four break points and hit 43 errors.
Nadal battles France's Richard Gasquet in his second-round match.
Italian Matteo Berrettini, Argentine Diego Schwartzman and France's Gael Monfils also advanced out of Tuesday's first-round matches.
Barty was the top women's player to advance Tuesday at Roland Garros. The No.1 player in the WTA rankings beat American Bernarda Pera 6-4, 3-6, 6-2.
Barty served five aces, one double fault, converted five of 12 break points and hit 25 errors as she played through a hip injury over 2 hours. The Australian battles Poland's Magda Linette in the second round.
"I accepted the fact that I was not absolutely 100%, but I'm certainly good enough to go out there and fight and do the best that I can to win matches," Barty told reporters.
"I'm not going to hide behind the fact that I'm not quite 100%, but I'm going to go out there with the right attitude every day."
Ukrainian Elina Svitolina, Greece's Maria Sakkari and Czechs Karolina Pliskova and Karolina Muchova also advanced Tuesday, as did Americans Sloane Stephens, Cori "Coco" Gauff, Varvara Lepchenko, Anni Li and Jennifer Brady.
Russian Ekaterina Alexandrova knocked out unseeded American Venus Williams in straight sets.
The second round of the French Open airs from 5 a.m. to 6 p.m. EDT Wednesday and Thursday on the Tennis Channel.