
Spain's 21-year-old king of clay was awaiting an opponent as top seed Roger Federer - losing finalist at the past two editions - faced Australian Open champion Novak Djokovic.
The Swiss holds a 5-2 lead over the Serb who defeated him in the Melbourne semi-finals three months ago.
Nadal improved to 3-1 over Russia's Davydenko as the top four players in the world contested semi-finals together for the first time since Cincinnati in 1999.
Spain's world number two broke early and late in the opening set to earn the lead after 44 minutes against Davydenko, who has dropped out of Barcelona next week after a nearly nonstop playing schedule.
The Russian has been on court almost continuously since March 3 in Dubai and has finally decided he needs a pause before the Rome Masters which begins a week from Monday.
The well-rested Nadal showed vigour as he got on top in the second set, earning a 3-1 lead before the Russian rallied to get back on serve with a break-back in the fifth game.
But Nadal was having no part of an upset as he rolled to 4-2 before finishing off the match in just over 90 minutes on his second match point.
The winner produced 13 winners, one lees than Davydenko, with Nadal breaking five times.
The three-time French Open champion has a huge ask this spring as he defends titles in the principality, Barcelona, Rome and the Grand Slam in Paris.
Nadal has not won a title since Stuttgart last July on clay.