The pair are due to meet in the semi-finals of the Australian Open later this week in a repeat of the 2009 final in Melbourne.
"We have played a lot of matches against each other," the Spaniard told reporters. "All are very important moments for our careers and very high moments.
"So the match is special. I don't know how many we have played, but most were finals or a few semi-finals in a Masters Cup.
"For what the match represents, it is always special against him."