Fifth-seeded Swede Joachim Johansson was ousted.
Sanchez defeated American Jan-Michael Gambill, 6-3, 6-4, and Volandri beat Czech Tomas Berdych, 6-3, 6-1. Russian Igor Andreev eliminated Johansson, 6-2, 7-6 (7-2).
Austrian Daniel Koellerer rallied past Italy's Davide Sanguinetti, 2-6, 6-2, 6-4, for his first career ATP Tour match win.
Also, Victor Hanescu of Romania blitzed German Alexander Popp, 6-4, 6-2, and Raemon Sluiter of the Netherlands got past Tomas Zib of the Czech Republic, 6-4, 2-6, 6-3.
Monday, top seed Andre Agassi of the United States makes his claycourt debut, a week away from the start of the French Open.