STOCKHOLM (AP) Gastao Elias of Portugal stunned top-seeded Gael Monfils 7-6(4), 6-1 in the second round of the Stockholm Open on Thursday.

Elias booked a slot in the quarterfinals against Jack Sock of the U.S., who edged Dustin Brown of Germany 7-6 (5), 4-6, 6-4.

Ranked 61 in the world, Elias saved four break points against the seventh-ranked Monfils. He celebrated the win by jumping into the air like Portuguese soccer star Cristiano Ronaldo.

No. 2-seeded Grigor Dimitrov also advanced by beating Jurgen Zopp of Estonia 6-3, 6-2, and will face Kevin Anderson of South Africa in the quarterfinals.

Anderson saved two set points in the first set to defeat Ryan Harrison of the U.S. 7-6 (8), 6-4.

Juan Martin del Potro set up a quarterfinal against Ivo Karlovic by beating Nicolas Almagro of Spain 3-6, 7-6 (1), 6-3.