Stockholm, Oct 20: James Blake of the United States upset second-seeded Juan Martin Del Potro of Argentina 6-4, 6-4 on Wednesday to reach the quarterfinals of the Swedish 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 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.