Gonzalez fell 6-4, 6-7 (8-10), 6-3 to Albert Ramos-Vinolas after having four service breaks. Hewitt was beaten by Eduardo Schwank 7-6 (7-3), 6-4. Schwank won only four more points -- 72-68 -- in the match but didn't drop a service game in advancing.
The other seeded players on Wednesday's card all advanced. Third-seeded Jo-Wilfried Tsonga led the way with a 6-3, 6-2 victory over Jan Hajek in 65 minutes. Tsonga fired off five aces and saved all five of the break-point situations he faced.
No. 5-seeded Fernando Verdasco made the third round with a 7-5, 6-3 win over Richard Gasquet while eighth-seeded David Ferrer took out Marcel Granollers 7-5, 6-4. No. 7-seeded Juan Carlos Ferrero was ahead 6-3, 4-2 when Sergiy Stakhovsky was unable to continue his match and retired.
Also, 11th-seeded Jurgen Melzer beat Oscar Hernandez 6-7 (4-7), 7-5, 7-5; 13th-seeded Thomaz Bellucci held on for a 6-2, 1-6, 7-5 win over Victor Hanescu; and 16th-seeded Feliciano Lopez slipped by Denis Istomin 7-6 (9-7), 7-5.
Unseeded players advancing to the third round Wednesday included Guillermo Garcia-Lopez, Simone Bolelli, Ernests Gulbis and Thiemo de Bakker.
Second-seeded Robin Soderling, No. 15 Nicolas Almagro and unseeded Ivan Navarro won their second-round matches Tuesday.