Defending champion Iga Swiatek overcame an early wobble to reach the French Open second round on Tuesday with a straights sets win over Cristina Bucsa of Spain.

The world number one, bidding to become the first woman to successfully defend the title at Roland Garros since Justine Henin in 2007, came through 6-4, 6-0.

"I know this court pretty well and I am focusing on the future," said Swiatek, who could lose the top ranking to Aryna Sabalenka or Elena Rybakina at Roland Garros.

Swiatek, the champion in Paris also in 2020, had dropped just one game to Bucsa when the pair met at the Australian Open in January.

She struggled for rhythm on Tuesday in a first set which featured five breaks of serve.

However, once the opener was wrapped up, the 21-year-old swept aside Bucsa, ranked 70 in the world, in a 22-minute second set.

Next up for Swiatek is a clash against Claire Liu of the United States. (AFP)