Ottawa: Britain reached the Davis Cup quarter-finals under bizarre circumstances on Sunday when Canadian Denis Shapovalov defaulted for inadvertently blasting a ball into the umpire's face.

Shapovalov, 17, had lost the first two sets against Kyle Edmund in the fifth and deciding rubber when he hammered the ball away in a fit of rage at 2-1 down in the third set.

Although he meant to hit the ball into the stands, it flew straight into the left eye of umpire Arnaud Gabas.

The Frenchman iced the wound, but could not continue and had no option but to disqualify Wimbledon boys' champion Shapovalov.

Gabas was being taken to Ottawa General Hospital for a precautionary evaluation.

Edmund had taken the first two sets 6-3, 6-4 and seemed on the way to victory in the third when everyone inside the arena was shocked by the sudden turn of events.

The win capped a fine comeback for Britain, who had come into the day leading 2-1 before Pospisil levelled the world group first round tie with a 7-6, 6-4, 3-6, 7-6 win over Dan Evans.

The victory means Britain will head to France for a quarter-final tie scheduled for April 7-9.

In other ties, Spain edged Croatia to advance and defending champions Argentina battled Italy into a decisive fifth match at a rain-hit tie.

Heavy rain in Buenos Aires interrupted Sunday's first match before Argentina's Carlos Berlocq defeated Italy's Paolo Lorenzo 4-6, 6-4, 6-1, 3-6, 6-3 to level the tie at 2-2.

In Frankfurt, Steve Darcis knocked off German teenager Alexander Zverev in four sets to send Belgium into the quarter-finals. (Agencies)