Dominic Thiem and Diego Schwartzman have both been eliminated from the Argentina Open, robbing the tournament of a grand slam champion and a local favourite.
Thiem, the 2020 US Open champion who is trying to regain his form after falling to 99th in the rankings, lost 6-4 6-4 to Juan Pablo Varillas.
Home-town Schwartzman was beaten by Bernabe Zapata Miralles 6-1 6-3.
Miralles will play another Argentine, Francisco Cerundolo, in the quarter-finals. Cerundolo beat Jaume Munar 6-2 6-1.
Third-seeded Lorenzo Musetti beat Pedro Cachin 6-2 6-3 and will face Varillas next.
In the other quarter-finals on Friday, top-seed and second-ranked Carlos Alcaraz faces Dusan Lajovic and second-seeded Cameron Norrie takes on Tomás Martin Etcheverry.