In-form Maria Sharapova added the sunshine with a yellow dress as she routed Mirjana Lucic 6-3, 6-0.

Siberian-born Sharapova has overcome serious elbow and shoulder injuries which have hampered the career of the three-times grand slam champion.

"I don't think any road is particularly easy. If you don't have the tough days and if you don't go through adversity, I don't think that the good ones and the wins mean as much as when everything seems to be going our way," the 24-year-old Russian told a news conference.

"I've put a lot of work in starting from the off-season. I had a tough period in the beginning of the year, being sick for a while and having to wait to play a tournament," she added.

"I was just really positive. I trained really hard."

Sharapova has enjoyed springtime in Europe.

"I have been to really cool cities in the last few weeks starting in Madrid and Rome and here, and I love walking around," she said.

"I find a lot of inspiration in street style and watching women walk, the way they wear things and what they're wearing. I take a lot of pictures. I do a lot of collages."

The Paris grand slam is the only one missing from Sharapova's collection but victory in the Rome International this month confirmed her return to form. 

Rafa Nadal suffered a severe fright before punching the air with both fists in joy as he began his French Open defence on Tuesday with a dogged win over John Isner, while fit-again Kim Clijsters sauntered through her first match.

World number one Nadal was forced into his first five-set match at Roland Garros and risked becoming the first men's champion to go out in the first round on the Paris clay before finally outlasting the giant American 6-4, 6-7, 6-7, 6-2, 6-4.

"It's always a very, very close match with John," Nadal said in a courtside interview. "I was there, I fought all the time. In the tiebreaks I was probably too nervous."

Queues at the entrances to the famous courts in western Paris lengthened as temperatures warmed up and anticipation rose for Nadal's first match.

The Spaniard is seeking a sixth title in seven years but Australian Open champion Novak Djokovic, who easily won his first match on Monday, is threatening to break his dominance after a stunning unbeaten start to the year.

American Isner is best known for his 11-hour epic match against Nicolas Mahut at Wimbledon last year and he made Nadal sweat profusely with his high-bouncing serve and surprising deftness at the net.

He dominated the two tiebreaks, winning 7-2 in both as Nadal struggled to cope with Isner's all-round game.

Yet, using an inner-strength he has shown so often on other surfaces, "King of clay" Nadal dug deep to break twice, take the fourth set and steal most of the momentum.

Isner lost his way in the final set, dropping serve in the third game as Nadal closed out a testing tussle to set up a second-round meeting with compatriot Pablo Andujar.

Ana Ivanovic rivalled the Russian in the fashion stakes with a pink number, but the tearful ex-champion lost 7-6, 0-6, 6-2 to Sweden's Johanna Larsson.

The 20th-seeded Serb, who withdrew from last week's Strasbourg International with a wrist injury, lacked consistency against the world number 64.

Ivanovic, who topped the world rankings in 2008 when she won at Roland Garros, seemed to have found her form when she rolled through a one-sided second set despite still battling to stem the unforced errors.

She went off the boil again in the sunshine on court Suzanne Lenglen in the decider and bowed out after one hour and 49 minutes when she netted a routine forehand.

Robin Soderling moved in to the second round after some difficult.

The two-time finalist, seeded fifth, was given an intensive first-round workout before he overcame American Ryan Harrison 6-1, 6-7 (5-7), 6-3, 7-5.

The 19-year-old Harrison only made the main draw after Benjamin Becker dropped out, but impressed again after making the last 16 at Indian Wells in March.

World number two Kim Clijsters avoided any mishaps in a 6-2, 6-3 first-round win over Belarussian Anastasiya Yakimova as she made her return to the French Open after a five-year absence on Tuesday.

The Belgian, who had been out for two months after a series of injuries including an ankle problem sustained while dancing at her cousin's wedding, proved her fitness by dismissing the world number 100 in 80 minutes.

Clijsters, who took a 1-1/2-year break from the sport, won on her fourth match point when Yakimova sent a forehand into the net and now faces Arantxa Rus of the Netherlands.

Although the Belgian's build-up to the claycourt grand slam was hampered by the dance incident, Clijsters was delighted to be back at Roland Garros and would not have missed it.

"That's one of the reasons why after Miami I took a little bit of a break, but (thought) always in mind, okay, I'm going to go and prepare myself," she told reporters.

"I'll take a couple of weeks off, 10 days off. I'll work out still and everything, kind of already with my mindset on the clay court season."