Champion style: Novak Djokovic celebrates a point against Marin Cilic

Madrid (AFP) - Novak Djokovic defeated Marin Cilic for the 18th time on Friday to keep Serbia alive in their Davis Cup semi-final clash with Croatia.

The world number one, unbeaten in singles in the tournament since 2011, triumphed 6-4, 6-2 to pull Serbia level at 1-1 in the tie.

It was the 20-time Grand Slam title winner’s 19th successive Davis Cup win.

Earlier Borna Gojo, ranked a lowly 279, pulled off a surprise win over world number 33 Dusan Lajovic, 4-6, 6-3, 6-2 to give Croatia the edge.

The semi-final will be decided when Djokovic and Filip Krajinovic, a late replacement for Nikola Cacic, tackle the world number one pairing of Nikola Mektic and Mate Pavic in the doubles.

Mektic and Pavic are the Wimbledon and Olympic champions.

Cilic, a former world number three now down at 30, carved out eight break points on the Djokovic serve but was unable to convert a single one.

Gojo has played well above his world ranking in the tournament so far and showed real mettle against Lajovic to come back from a set down, especially after letting slip a 4-2 and 40-0 lead in the first set, losing 17 of the next 18 points.

He also saw off Italy’s Lorenzo Sonego (ranked 27) in the quarter-final and Australia’s Alexei Popyrin (67) in the group stages.

Croatia's Borna Gojo rich run of form continued as the 279th-ranked player pulled off a surprise three sets win over Serbian Dusan Lajovic to put the Croats 1-0 up in their Davis Cup semi-final

“In the first set I was up 4-2 40-0, I was in control, I slipped in that game there. I got down on myself a little bit, but then the captain and the teams and the fans picked me back up,” said Gojo.

“Obviously Davis Cup is a special competition where the pressure is bigger on everyone and I managed to play some of my best tennis here at this tournament.

“I’m very happy that I managed to get those big wins, ranking wise, but for me it’s more important that I managed to get the point for the team.”

Serbia have defeated their Balkan neighbours in their two previous Davis Cup meetings.

The first came in Split in 2010 when Serbia won 4-1 in the quarter-finals en route to winning the competition.

They also romped to a 5-0 thrashing in 2015.

Serbia, who crept through to the last eight as one of the two best runners-up, are bidding to reach a third Davis Cup final and two-time winners Croatia, who topped their group, a fourth.

The winners will face either Russia or Germany, who play on Saturday, in Sunday’s final.