Poland's Iga Swiatek launched her bid for Olympic gold with a 6-2, 7-5 win over battling Romanian Irina-Camelia Begu in the opening round of the singles on Saturday.

Fifty days after clinching a fourth French Open title, the 23-year-old Swiatek returned to the Parisian clay and showed why she is favorite to add the Olympic crown to her resume.

The opening day of the tennis event was disrupted by heavy rain with thousands of spectators without tickets for the two main show courts left frustrated after queuing to get in.

Play will not start until 3 p.m. local time on the uncovered courts, organizers said.

Action began on time under the Court Philippe Chatrier roof, however, and on Court Suzanne Lenglen where Italy's fourth seed Jasmine Paolini, runner-up to Swiatek in the French Open, beat Romania's Ana Bogdan 7-5, 6-3.

Men's top seed Novak Djokovic, bidding to win his first Olympic gold, takes on Australian Matthew Ebden later while second seed Carlos Alcaraz faces Lebanon's Hady Habib.

The evening session will be headlined by Alcaraz and Rafael Nadal, fresh from his Olympic torch-carrying responsibilities, combining in the men's doubles first round.

Top seed Swiatek is dubbed the queen of clay and is the overwhelming favorite to win the gold medal. But she was made to work hard by Begu, especially in the second set in which she trailed 5-3. Swiatek found an extra gear when she required it, however, and reeled off four games in a row to move through, sealing victory when Begu double-faulted.

Results from all the Olympic tennis women's singles first round matches.