Second-seeded Fernando Verdasco of Spain was knocked out in the first round of the Mexican Open, losing 6-2, 4-6, 6-3 to Brazil's Thomaz Bellucci on Tuesday.
Verdasco was bundled out in the first round of the RMK Championships in Memphis last week by Milos Raonic, who beat him in the SAP Open title the previous week.
Bellucci converted 75 percent of his break points and won 70 percent of his service points to beat Verdasco in just over two hours late on Tuesday.
Earlier, third-seeded Nicolas Almagro of Spain took a confident step toward his third straight title with an easy 6-3, 6-2 win over Victor Hanescu of Romania.
Almagro won the Copa Claro on Sunday in Buenos Aires and the Brazil Open the week before- both on clay, the surface in Mexico.
Fourth-seeded Stanislas Wawrinka of Switzerland also got off to a winning start, defeating Pablo Andujar of Spain 7-6 (5), 7-6 (3) in the joint ATP and WTA event in Mexico's Pacific coastal resort.
Defending champion and top-seeded David Ferrer reached the second round on Monday.
Fifth-seeded Albert Montanes of Spain defeated countryman Daniel Gimeno-Traver 6-2, 6-1, and seventh-seeded Juan Monaco of Argentina moved on to the second round after defeating countryman Horacio Zeballos 7-5, 7-6 (3).
There was bad news for No. 8 Juan Ignacio Chela, who retired in the second set against fellow Argentine Eduardo Schwank with the scores at 3-6, 6-5.
Chela was named Monday to Argentina's Davis Cup team for a March 4-6 first-round match against Romania. David Nalbandian was also named to the team, but withdrew from this event with a groin injury.
On the women's side, Loudres Dominguez Lino of Spain eliminated second-seeded Polona Hercog of Slovenia 6-3, 4-6, 6-3. No. 5 Simona Halep of Romania also bowed out with Laura Pous-Tio of Spain winning 6-3, 6-7 (4), 6-3.
No. 3 Greta Arn of Hungary defeated Edina Gallovits-Hall of Romania 6-4, 6-4, and No. 4 Gisela Dulko of Argentina advanced against Anna Tatishvili of Georgia 6-3, 6-1. No. 7-seeded Carla Suarez Navarro of Spain downed Sandra Zahlavova of the Czech Republic 6-4, 6-1.
Top-seeded Julia Goerges of Germany won her first-round match on Monday.