MONTREAL -- Canada missed its chance to clinch its Davis Cup World Group qualifying tie with South Africa on Saturday, falling in straight sets in doubles competition.

Izak van der Merwe and Raven Klaasen defeated Toronto's Daniel Nestor and Vancouver's Vasek Pospisil 6-4, 7-6, 7-6 to earn South Africa's first win in the best-of-five series at Uniprix Stadium.

The visitors, who have been playing with an injury-depleted roster, clinched their first set win of the tie by rallying from a 4-3 deficit with three straight game wins.

Nestor and Pospisil seemed to be on their way to evening up the sets at one apiece, leading 5-2 through seven games. But van der Merwe and Klaasen began their comeback.

After holding serve in the eighth game, the South African pair benefited from three double faults by Canada to cut the lead to 5-4. Canadians recorded eight of its 10 double faults in the second set.

South Africa then held serve to even up the set, 5-5 before Canada reclaimed the lead. But van der Merwe and Klaasen tied the set again and won the tiebreaker 7-3.

Canada trailed the third set 5-2 before reeling off three straight wins to tie it at 5-5.

Van der Merwe held serve to take the lead but Canada did the same to knot it up, 6-6.

Nestor and Pospisil pulled themselves into a tie twice in the tiebreaker before eventually losing 7-5.

Canada now needs one win in Sunday's two singles rubber matches to stay in the World Group.