Serbia are closing in on an ATP Cup semi-final berth after Dusan Lajovic piled more misery on Canadian young gun Felix Auger-Aliassime.

Lajovic put Serbia one up in Friday’s third quarter-final with a resounding 6-4 6-2 win over a badly out-of-sorts Auger-Aliassime.

After opening the competition with victory over Greek world No.486 Michail Pervolarakis, Auger-Aliassime, rated one of the hottest prospects in tennis, has failed to win a set in his past three matches against John Millman, Jan-Lennard Struff and now Lajovic.

His latest flop has heaped the pressure on fellow prodigy Denis Shapovalov, who must beat world No.2 and reigning Australian Open champion Novak Djkovic in the second singles rubber to send the quarter-final to a deciding doubles match.

Djokovic is making his first appearance in Sydney in a decade.

And in a rare treat for Sydney fans, world No.1 Rafael Nadal will be in action on Friday night when he leads Spain into quarter-final battle with Belgium.

A tasty semi-final encounter with Australia on Saturday night looms large for Spain if the Davis Cup champions can continue on their merry way.

Nadal will be a warm favourite to down David Goffin in their top-seed encounter while Roberto Bautista Agut will be just as short odds against Steve Darcis.

It’s also a rare venture to Sydney for the 19-time grand slam champion who was involved in the Fast4 tournament last year but has not played an ATP tournament in the city since turning pro in 2001.

Nadal is undefeated in ATP Cup singles and holds a 4-1 lifetime record against world No.11 Goffin.

In the other tie Russia, spearheaded by world No.5 Daniil Medvedev, beat Argentina to progress to the last four.

Serbia or Canada will play Russia in Saturday’s first semi-final.