Leander Paes and Martin Damm of the Czech Republic upset the second seeded pair of Sweden's Jonas Bjorkman and Max Mirnyi of Belarus to enter the semi-finals of the ATP Masters Series event in Toronto, Canada.

Paes and Damm, seeded seventh, won 7-6 (7/4) 7-5 in the quarter-finals on Friday.

They will next take on the third seeds Paul Hanley of Australia and Zimbabwean Kevin Ullyett, who defeated Australian Wayne Arthurs and Slovakia's Dominic Hrbaty in 6-4, 6-3 their quarter-final.

Top seeds Bryan brothers -- Bob and Mike -- will take on the fourth seeds Canadian Daniel Nestor and Mark Knowles of Bahamas in another semi-final.

The American siblings edged past the fifth seeded pairing of Frenchman Fabrice Santoro and Serbian Nenad Zimonjic in a marathon three-setter 3-6, 6-4, 10-7, while Knowles and Nestor defeated Sweden's Simon Aspelin and Australian Todd Perry 2-6, 6-3, 10-2.