Nadal was a four-time defending champion and had won his previous 31 French Open matches. He hadn't lost a set this year in Paris until the 23rd-seeded Soderling broke Nadal's serve twice in taking Sunday's first set 6-2.
Nadal won a second-set tiebreaker but Soderling was able to finish off the match 6-2, 6-7 (2-7), 6-4, 7-6 (7-2). Soderling had 61 winners and overcame 59 unforced errors, suggesting a very aggressive approach in facing Nadal.
Soderling moves to the French Open quarterfinals against 10th-seeded Nikolay Davydenko, who was very solid in a 6-2, 6-2, 6-4 win over No. 8-seeded Fernando Verdasco. Davydenko made just six unforced errors while getting 77 percent of his first serves in.
In other fourth-round matches Sunday, world No. 3 Andy Murray defeated 13th-seeded Marin Cilic 7-5, 7-6 (7-4), 6-1 and 12th-seeded Fernando Gonzalez advanced with a 6-2, 6-4, 6-2 win over 30th-seeded Victor Hanescu. Murray and Gonzalez will meet in the quarterfinals.
Murray piled up 10 aces and had 14 unforced errors in his match. He's lost one set in his first four French Open matches this year.
Gonzalez has yet to lose a set in Paris. He didn't face a break point against Hanescu and fired off 50 winners in the 87-minute match.