Söderling marched into his first ever Grand Slam semi-final with a superb 6-1, 6-3, 6-1 win in Paris on Tuesday.
Söderling, the 23rd seed and world number 25, will play either British third seed Andy Murray or Chile’s 12th seed Fernando Gonzalez for a place in the final.
The 24-year-old shocked the sporting world by inflicting a first ever Roland Garros defeat on four-time champion Nadal on Sunday and becomes the first Swedish French Open semi-finalist since his coach Magnus Norman in 2000.
“I didn’t have a very easy draw,” said Söderling, who also overcame Spanish 14th seed David Ferrer in the third round.
“I’ve played three good claycourt players and I’ve played three very good matches, so my confidence is getting better and better.
“It was maybe easier than I expected (against Davydenko). You expect a tougher match in the quarter-finals of a Grand Slam, but it wasn’t as easy as the scoreline suggested.
“I always knew I could play really, really good tennis when I’m on top of my game. But what I’m happiest about is that I’ve played well for many matches in a row, which was maybe missing a few years ago.”
Söderling survived two break points in his opening service game before breaking Davydenko twice in succession, the Russian netting backhands at the critical moment on both occasions.
Davydenko, playing on his 28th birthday, was at times made to look statuesque by Söderling’s strafing groundstrokes and pinpoint returning, with the Swede wrapping up the first set in just 23 minutes.
World number 11 Davydenko, a Roland Garros semi-finalist in 2005 and 2007, saved four break points early in the second set, but Söderling refused to be deterred, finally securing the break in game seven when Davydenko found the net with a forehand.
Söderling’s inspired shot-making continued as he opened up a two-set lead and he totted up yet more sensational winners in an uncompetitive third set to prolong his fairytale run on the Paris clay.
“He surprised me, he played really well,” said Davydenko.
“I tried to play better, to get some control from the baseline and play some long rallies with some top-spin, but he kept making winners. He just played faster.”