Spain, the defending champions and top seeds, will play Argentina for a place in the quarter-finals, a vital match for both countries because teams reaching the last eight qualify for the World Group when the competition changes to a Davis Cup style format next year.
Martinez needed 33 minutes to beat the 20-year-old Alejandra Quezada. Keeping her opponent continually wrong-footed, Martinez conceded only one game.
Sanchez Vicario outplayed Paula Cabezas, Chile's top player, by the same 6-1, 6-0 score in 51 minutes. The two then combined for a 40-minute 6-0, 6-1 victory in the doubles.
The United States, the second seeds, beat the Czech Republic, but they did not have things all their own way. Mary Joe Fernandez struggled in the second set but beat Petra Langrova 6-2, 6-4, while Lindsay Davenport had an up and down match before winning 4-6, 6-1, 6-4 against Ludmila Richterova.
Belgium became the first seeds to make an exit when they lost the doubles in their unfinished tie against Sweden. Dominique Monami and Sabine Appelmans resumed with a one-set lead but lost the next two sets to Maria Strandlund and Maria Lindstrom.Reuse content