Stockholm - James Blake of the United States upset second-seeded Juan Martin Del Potro of Argentina 6-4, 6-4 on Wednesday to reach the quarter-finals of the Stockholm Open.
South Africa's Kevin Anderson and Milos Raonic of Canada also advanced in the Royal Tennis Hall.
Anderson needed three sets to beat 33-year-old Tommy Haas of Germany 6-7 (3), 6-4, 6-4 while Raonic easily defeated Philipp Petzschner of Germany 6-3, 6-3.
In other action on Wednesday, Bernard Tomic of Australia beat Estonia's Jurgen Zopp 7-6 (5), 4-6, 6-0 to reach the second round, along with Grigor Dimitrov of Bulgaria, who defeated Ryan Sweeting of the United States 6-3, 6-1.
German Sebastian Rieschick is also through to the second round after beating home crowd favorite Michael Ryderstedt of Sweden, 6-4, 3-6, 6-3.
Results on Wednesday at the Stockholm Open (seedings in parentheses):
Bernard Tomic, Australia, def. Jurgen Zopp (Estonia), 7-6 (5), 4-6, 6-0.
Grigor Dimitrov, Bulgaria, def. Ryan Sweeting, United States, 6-3, 6-1.
Sebastian Rieschick, Germany, def. Michael Ryderstedt, Sweden, 6-4, 3-6, 6-3.<
Kevin Anderson (5), South Africa, def. Tommy Haas, Germany, 6-7 (3), 6-4, 6-4.
James Blake, United States, def. Juan Martin Del Potro (2), Argentina, 6-4, 6-4.