Rio de Janeiro, Feb 21 (IANS): Spain's Jaume Munar, Bolivia's Hugo Dellien, Slovenia's Aljaz Bedene and Canada's Felix Auger-Aliassime have advanced to the quarter-finals of the Rio Open tennis meet.

Favourites Dominic Thiem of Austria and Fabio Fognini of Italy were eliminated in the first round of the tournament, reports Efe news.

Munar, with an ATP ranking of 66, will face Auger-Aliassime (64) in the quarters while Dellien (113), the big surprise of the event, will play Bedene (83).

The other quarter-finalists will be decided later on Thursday in the matches between Laslo Djere and Taro Daniel, Casper Ruud and Joao Sousa, Federico Delbonis and Albert Ramos and Pablo Cuevas and Juan Ignacio Londero.

The 2016 champion Cuevas was the last to qualify for the round-of-16 with a win against defending champion Diego Schwartzman of Argentina, who retired due to injury while trailing 6-4, 4-1.

Austria's Thiem was ousted in the first round this time around along with the Italians Fabio Fognini (16) and Marco Cecchinato (17).

Out of the top eight seeded players of the event, Portugal's Joao Sousa (40), fifth favourite, was the only one to move into the second round while Serbia's Dusan Lajovic (43), Tunisia's Malek Jaziri (44) and Chile's Nicolas Jarry (47) were all knocked out.

Their elimination opened the door for youngsters such as Munar and Auger-Aliassime and the surprise package Dellien.

Munar, 21, bagged a place in the quarter-finals after a 7-6 (6), 5-7, 7-6 (4) win against Britain's Cameron Norrie (62) in a match lasting 3 hours and 19 minutes that was only decided in the tie-breaker.

The Spaniard let three set points slip away and lost the opportunity to wrap up the match in the second set itself or earlier in the third set without the tie-breaker.

Dellien ousted Spain's Roberto Carballes (114) 7-5, 6-4 to become the first Bolivian in 39 years to reach the quarter-finals of such a competition.

The Slovenian Bedene booked his spot in the quarters with a 6-3, 6-4 victory against Brazil's Thiago Monteiro (126).

In the first round, Bedene had defeated Italy's Marco Cecchinato, who won the Argentina Open on Sunday.

The last player to make it to the quarter-finals on Wednesday was 18-year-old Canadian Auger-Aliassime, who beat Chile's Christian Garin (91) 7-5, 6-4 in one hour and 46 minutes.

The Canadian, who has reached his first ATP 500 quarter-finals, had pulled off a surprise win against Fognini (16), the second favourite, in the first round on Tuesday.