Not once since the tournament first welcomed foreigners in 1925 had a champion -- man or woman -- fallen at the first hurdle the following year. Under clear Parisian skies, Costa came mightily close to becoming the first.
But when it mattered, Argentine Sergio Roitman's nerve failed him and he allowed Costa off the hook to squeeze out a face-saving 6-7, 2-6, 7-5, 6-2, 6-2 win.
Having trailed by two sets and 4-2 it was an escape of some proportions and one which the ninth-seeded Spaniard was lucky to pull off after three hours and 38 minutes.
"It is completely different from last year. Last year, I was playing very well. Here, I'm not playing my best tennis at all," Costa said afterwards, still clearly relieved at surviving the ordeal.
"I'm not thinking about winning the tournament or anything. I'm just happy to have a chance to play a second match," he said.
CREDIBLE THREAT
American sixth seed Andy Roddick was made to suffer for his lukewarm performance and was ousted by Armenian muscleman Sargis Sargsian 6-7, 6-1, 6-2, 6-4.
It was the American's second successive first round loss in Paris and a big disappointment since he had won his sixth title in St Poelten on clay last week.
Former three-times champion Monica Seles also suffered ignominy. Seeded 12th this year, Seles was steamrollered by Russia's Nadia Petrova 6-4, 6-0. It was her worst-ever defeat at Roland Garros. She had never before failed to reach the quarter-finals in 10 previous visits.
Women's third seed Venus Williams managed to advance despite a mediocre show, beating fellow American Samantha Reeves 6-2, 6-4.
But there was never a hint of disappointment for Clijsters as she walloped Amy Frazier and, although boyfriend Hewitt had looked a little out of touch against Brian Vahaly, the winner of that match was never really an issue either.
Britain's Tim Henman put his recent poor form and injury worries behind him to thrash Belarussian Vladimir Voltchkov 6-2, 6-3, 6-1.
Henman has struggled with his right shoulder since surgery last December and had won just four matches all year. Voltchkov posed no credible threat, though. The last time he won on clay was in a Davis Cup match against Morocco in 1998.
Roitman, by contrast, posed a very real threat to the survival of the tournament's 2002
Granted a place in the main draw despite losing in qualifying, the so-called 'Lucky Loser' rode that luck for 2 1/2 sets before seeing his dream disappear in the French capital.
Costa scrapped and chased, hustled and harried before finally overcoming the Argentine.
Clijsters was never in such trouble as the women's second seed nailed her American opponent 6-2, 6-0 in 45 minutes.
Packing both a heavyweight punch and a featherlight touch, the Belgian floored Frazier with ease. Frazier's usual ghostly pale visage grew redder and redder as the sun beat down and Clijsters ran her this way and that throughout the contest.
COMPETENT PROFESSIONAL
Frazier -- a competent professional with 16 years experience on the WTA Tour -- was simply made to look clumsy as Clijsters rattled off a straightforward victory.
Clijsters' boyfriend Hewitt did enough to win but displayed nothing like the form that has made him world number one.
The Australian toiled for more than three hours on the slow, red clay to overcome an opponent ranked 76th in the world.
After winning a closely contested first set 6-4 in 55 minutes, Hewitt showed Vahaly no mercy in the second, unleashing a series of devastating forehand winners from the baseline to take it 6-1.
Hewitt lost his touch in the next set, though, and wasted three match points in the tiebreak -- hitting a double fault on the third -- before losing it 8-6. He won the match by taking the fourth set 6-3.
"Playing on clay is always a tough situation for me as I only play on the surface for a few weeks of the year," the 22- year-old said.
Hewitt will face Russian Nikolay Davydenko, who beat Briton Greg Rusedski 6-3, 7-5, 6-2.
Former women's champion Jennifer Capriati romped into the second round, trouncing South African Joannette Kruger 6-2, 6-1.
Sixth seed Lindsay Davenport, of the U.S. joined her, the newly-wed beating Indonesia's Wynne Prakusya 6-2 while 10th seed Jelena Dokic, playing under the Yugoslav flag, beat Germany's Angelika Roesch 6-4, 6-4.