World number one Andy Roddick survived a tough first-round clash at the Australian Open, but it was a day to forget while for 2003 finalist Rainer Schuettler.
Roddick beat Chile's Fernando Gonzalez in straight sets but Schuettler, who has not won a match this year, surrendered a two-set lead to Swedish teenager Robin Soderling, going down 4-6, 4-6, 7-5, 6-3 ,6-4 in the Rod Laver Arena.
Schuettler was the surprise finalist last year, beating Roddick in the semi-finals before losing to Andre Agassi.
Soderling will play Nicolas Escude in the second round after the Frenchman beat Hyung Taik-Lee 6-3 7-6 (7/5) 6-2.
Three-time French Open champion Gustavo Kuerten was pushed the distance, but the Brazilian held on for a dramatic 5-7 6-0 6-1 2-6 8-6 victory over a resilient John van Lottum.
Kuerten, who has never been further than the second round at Melbourne Park, will play Croatian Ivan Ljubicic.
Frenchman Arnaud Clement, seeded 30, also lost a two-set lead, going down to Nikolay Davydenko of Russia 7-6 (8/6) 6-4 4-6 1-6 2-6.
Of the other seeds, Vince Spadea (29) lost in four sets to Thomas Enqvist, Spain's Tommy Robredo (20) was beaten by Argentine Gaston Gaudio 6-3 6-2 7-6 (8/6) and crowd favourite Younes El Aynaoui (18) was forced to retire.
His participation was always in doubt after he withdrew from the Commonwealth Bank International last week with a foot injury that has caused him concern for some time. The Moroccan was trailing Gala Blanco of Spain 4-1 when he retired.
Carlos Moya, as was widely expected, pulled out of his first round match against James Blake with the ankle injury suffered in the adidas International final against Lleyton Hewitt on Saturday.
In the woman's event world number one Justine Henin-Hardenne taught 15-year-old schoolgirl Olivia Lukaszewicz a harsh Grand Slam lesson but not all the seeds were as impressive on the first day of the Australian Open.
Henin-Hardenne, the French and US Open champion, took just 45 minutes to whitewash the Australian world number 870 6-0 6-0 on Rod Laver Arena.
While Amelie Mauresmo and Lindsay Davenport marched on, three of the women's seeds stumbled. Russian seventh seed Elena Dementieva was the highest to be eliminated, beaten 6-1 6-4 by rising Slovakian star Jelena Jankovic, the world number 79.
Dementieva was followed out by 10th seeded Russian Nadia Petrova, who lost to 20-year-old Hungarian Aniko Kapros 6-3 6-3 and Thailand's Tamarine Tanasugarn.
But Jankovic's victory was the biggest surprise of the opening day at the season's first Grand Slam.
Mauresmo, the fourth seed, beat Taipei's Chia-Jung Chuang 6-1 6-0 while Davenport, who has been nursing a strained shoulder muscle, still managed to pull off a comfortable 6-2 6-3 win over Ruxandra Dramgomir Ilie of Romania.
Bulgarian Magdelena Maleeva breezed past American Samantha Reeves 6-1 6-0 to book a second-round meeting with Petra Mandula who overcame Gala Leon Garcia 6-4 4-6 6-4.