Pavel defeated Martin 6-1, 6-3 and will face another Spaniard next, Albert Portas, on Thursday. The Romanian improved his clay court record to 15-8, which includes the quarterfinals at the French Open, Kitzbuehel and Stuttgart.
A bad right hamstring forced 2000 Romanian Open winner Juan Balcells to retire against Romanian wild card entry Victor Hanescu while trailing 6-7 (3-7), 1-1. Hanescu won for just the fourth time on the ATP tour this year and first since July.
In other completed matches on a day shortened by rain, Austria's Jurgen Melzer upset No. 6 Albert Montanes of Spain, 6-4, 6-4, and Spanish qualifier Juan Giner beat Croatian Zeljko Krajan, 6-3, 6-4. Also, David Ferrer of Spain defeated Andrea Gaudenzi of Italy, 4-6, 6-1, 6-0. Ferrer will play Melzer in the second round on Wednesday.
Christophe Rochus of Belgium advanced when Romanian wild card entry Gabriel Trifu retired with a hip injury with Rochus leading, 7-5, 5-5.
Two matches will be completed Wednesday, with No. 5 Jose Acasuso of Argentina up 3-2 against Belgian Dick Norman and Irakli Labadze ahead of eight seeded Adrian Voinea of Romania, 2-1.