Novak Djokovic and Ana Ivanovic had to display stiff resistance to reach the second round of the French Open in Paris on Sunday.
The popular Serbian duo had been expected to stroll past their little-known opponents but instead had to weather a barrage of winning shots before finally emerging victorious.
Australian Open champion Djokovic stood firm to record a 4-6, 6-3, 7-5, 6-2 win over Germany's Denis Gremelmayr while last year's runner-up Ivanovic battled past Sweden's Sofia Arvidsson 6-2, 7-5.
Djokovic came into the tournament with the reputation of posing the biggest threat to Rafael Nadal's hopes of capturing a fourth Roland Garros trophy but during the first set he was made to look like a novice on clay.
Before Djokovic even had a chance to soak up the atmosphere on the opening day of the championships, he was 4-0 down.
Eventually, he made his experience count to wear down Gremelmayr in two hours 29 minutes.
"I'm not really happy with my performance today. I played pretty passively and he used it, he was taking chances and deserved to win the first set," said Djokovic, who was beaten by Nadal in the semi-finals last year.
Touted as one of the favourites for the women's title following the shock retirement of Justine Henin two weeks ago, Ivanovic lit up a dark and overcast day when she stepped on Centre Court looking pretty in pink.
It was not long though before she felt the weight of expectation on her shoulders and her game started to spiral out of control.
After sweeping through the first set, Ivanovic began to produce unforced errors and she looked to be heading towards a third set.
Arvidsson had points to extend her 3-1 lead into a double break but Ivanovic, in the nick of time, rediscovered the touch that took her all the way to the final 12 months ago.
On securing victory with a backhand winner, she celebrated the moment with a trademark squeal.
"This year I'm number two and obviously have more expectations for myself, so that's something I'm still learning how to deal with," said Ivanovic, who produced 30 unforced errors during her 96-minute contest.
In the absence of an injured Andy Roddick, James Blake shoulders the responsibility of ending the US's men's Grand Slam drought which dates back to 2003.
The American stepped up to the challenge with a convincing 6-4, 6-1, 7-6 win over Germany's Rainer Schuettler.
Former semi-finalist Nicole Vaidisova was not so fortunate.
She failed to snap her wretched run of form when she became the first seeded casualty, thumped 7-6, 6-1 by friend and fellow Czech Iveta Benesova. It was her sixth successive defeat in 2008.
David Nalbandian, who has remained a perennial underachiever on the Grand Slam stage since reaching the Wimbledon final in 2002, demolished Argentine compatriot Carlos Berlocq 6-2, 6-4, 6-1 with the minimum of fuss.
Later on Sunday, three-times former champion Gustavo Kuerten begins his farewell appearance in Paris against French hope Paul-Henri Mathieu while Serena Williams, the only former winner in the women's draw, will face fellow American Ashley Harkleroad.
