STOCKHOLM, Sweden -- Former No. 1 Marcelo Rios and Nicolas Massu won second-round matches in different fashion Thursday, advancing to the quarterfinals in the Stockholm Open.

Thailand's Paradorn Srichaphan continued his surge through the draw as he took out France's Michael Llodra 6-4, 6-3.

Srichaphan, who made the round of eight in Madrid last week, his first quarterfinal at a Masters Series event, has not dropped a set in his two matches at the Royal Tennis Hall.

Cheered on by scores of flag-waving Chilean fans at the Royal Tennis Hall, Rios only needed to play one set before Jan-Michael Gambill was forced to retire due to a knee inflammation.

"It's playing like home,'' said Rios, who won the set 6-2. "It's very nice. It's one of the reasons why I came back this year. It's always nice to play on a center-court full with Chileans.''

The sixth-seeded Rios also played last year in Sweden, a country populated by more than 40,000 Chileans. But lost to former three-time champion Thomas Enqvist in the quarterfinals.

Rios has won at least one title each year since 1995, but he's running out of chances to extend that streak. Stockholm could be his last chance. Next week's Paris Masters is the last tournament, and has a much stronger field than Stockholm.

Massu had a much tougher time, outlasting No. 8 seed Rainer Schuettler of Germany 4-6, 7-6 (4), 6-3. The Chileans are both on the bottom half of the draw and could face each other in the semifinals.

Rios and Swedish qualifier Andreas Vinciguerra -- the two lefties left in the tournament -- will meet in the quarterfinals Friday. Vinciguerra beat third-seeded Guillermo Canas of Argentina 7-6 (5), 6-2. Canas, a semifinalist last year, had won their two previous matches.

Gambill, who lost to eventual champion Andre Agassi in the second round at the Tennis Masters Series-Madrid last week, was one of three Americans eliminated Thursday.

Morocco's Hicham Arazi beat hard-serving Taylor Dent 6-4, 6-2, and Tommy Robredo of Spain scored a hard-fought 6-4, 3-6, 7-6 (2) win over former Stockholm Open champion Todd Martin.

Fabrice Santoro, another Frenchman who reached the Madrid semis as a qualifier, struggled past Swedish qualifier Joachim Johansson of Sweden, 6-7 (6), 6-4, 7-6 (5).

In Friday's other quarterfinals, it's Robredo against Santoro and Massu against Arazi. Paradorn will face Raemon Sluiter, who defeated top-ranked Lleyton Hewitt on Wednesday.