Nadal broke Robert Farah of Colombia in the first game on his way to a 6-2, 6-3 victory for his 31st straight win at the tournament. Nadal set up a quarterfinal match with fifth-seeded Janko Tipsarevic after the Serbian beat Frederico Gil 6-2, 6-2.
"It may sound stupid, but against players like him, you have to go for victory, if you look for a fight you've already lost," Tipsarevic said. "Rafa is playing like he always does on clay, the best, but I'll go out there looking to win and see what happens."
Nadal beat Tipsarevic 6-1, 6-0, 6-2 in their previous meeting, which came in the Davis Cup three years ago.
Murray made quick work of another Colombian in a 6-1, 6-2 win over Santiago Giraldo, the fourth-ranked Briton serving up nine aces in a quick victory.