Andy Roddick won a battle of former champions, taming fourth seed Novak Djokovic of Serbia 6-4 7-6 in a quarter-final slugfest at the Montreal Masters.
Fifth seed Roddick, the 2003 winner, advances to the semi-finals where he will face either Rafael Nadal or Juan Martin Del Potro of Argentina.
The other semi-final will feature third-seeded Briton Andy Murray against Jo-Wilfried Tsonga of France, who staged a spectacular third set comeback to beat world number one Roger Federer in their quarter final.
Federer was up 5-1 before Tsonga won the set 7-6.
It was Fderers first tournament since winning Wimbledon and the birth of his twin daughters.
World numvber two Rafael Nadal playing his first tournament since his early exit from the french Open was beaten in two sets by Argentinian Juan Del Potro in two sets, 7-6, 6-1.
Roddick says he was happy with the win even though he was not serving well.
He and Djokovic spent much of the opening set trading bombs from the baseline, Roddick collecting the only break to take control at 4-3.
With players breaking each other in a tight second set, Roddick again showed his pedigree under pressure, winning the tie-break 7-4, his fourth out of four in Montreal.
Roddick, who leads the ATP with a 33-8 record in tie-breaks, also extended his dominance over Djokovic, who he has beaten in all three quarter finals against the Serb this year.
Andy Murray is the fourth semi finalist after beating Russia's Nikolay Davydenko 6-2, 6-4.