Djokovic's performance level was reminiscent of Federer at his peak, just annihilating a top player like that. There are only 2 players in the draw who could even give him a game when he plays like that.
Ferrer just picked up where he left off in the QF, on terrible form. He was at his worst and Djokovic was at his best. Let's not forget that Ferrer has a 5-10 record vs Djokovic, their matches aren't usually 1 way traffic.
Yes, but let's put those 5 wins in context:
1. Romania 2004, on clay, Novak was 17 years old, ranked 272 and he still took a set off Ferrer
2. Montecarlo 2007. Straight sets for David. Good win
3. Masters Cup, Beijing: Nole was exhausted after having his breakthrough season, he had entered too many tornaments not expecting to go so deep in so many, so he didn't win a single RR match at the end of the season, although he had clinched the #3.
4. 2009, Davis Cup, Clay, Spain. Ferrer winning a Davis Cp match at home, not really a surprise.
5. WTF, London, 2011. Again, Nole exhausted after his fabulous 2011 season. Nole's end of the season was less than perfect, remember?
So yes, Ferru has beaten Nole 5 times. All credit to him, but one shouldn't give all of those wins the same weight when trying to make a fair assessment of how these 2 players stand with respect to each other.
It's a question of matchup: I think David has a real problem against the top players. I think of the big four, he would rather face Murray before anybody else. He has a better chance.