'Truly wild': Novak Djokovic 'sorry' after blowing up at fans

Rowdy Serbian fans received a serve then later an apology from Novak Djokovic as the world No.2 breathed a sigh of relief after outlasting South Africa's Kevin Anderson at the ATP Cup in Brisbane.

A pumped up Djokovic gladly soaked up the fanatical Serbian supporters' applause after finally overcoming world No.91 Anderson 7-6 (7-5) 7-6 (8-6) to seal victory for his country in their opening tie, ending an epic clash lasting almost two and a half hours.

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But in the first set the Serbian fans' passion wasn't so appreciated by the 16-time grand slam champion.

Frustrated after former world No.5 Anderson fought back from 4-1 down to force a tiebreaker, Djokovic cut an annoyed figure as Serbian fans called out during points.

He finally exploded after taking a 3-2 lead in the tiebreaker, jumping up and down while screaming and gesticulating wildly at fans to be quiet.

If his rabid fan base were offended it didn't show as they cheered him on to victory, albeit not during points.

Djokovic was a relieved man after a harder than expected season opening clash against an opponent who had not played for six months due to knee surgery.

But he quickly became sheepish when he fronted the media and was reminded of his first set outburst.

"The Serbian crowd was a little too excited," he said.

"It (outburst) was in the heat of the moment and I am sorry if I offended anyone.

"It (calling out) happened a couple of points in a row and at 3-2 in the tiebreaker I didn't need them interfering in the point.

"But I am thankful for their support. It was a Davis Cup-like atmosphere. The Serbian guys showed great passion."

The vocal Serbian crowd was a blessing and a curse for Novak Djokovic in his ATC Cup match against Kevin Anderson. (Photo by PATRICK HAMILTON/AFP /AFP via Getty Images)

While Djokovic admitted he got more than he bargained for from Anderson, he said it was just what he needed as he prepared to claim a record eighth Australian Open title this month.

"His absence from the tour obviously didn't affect his game too much," Djokovic said of Anderson, who last played a match in July at Wimbledon.

"I got more than I thought I would get.

"But I thought it was a fantastic opening match of the season. He was playing at a very high level."

Dual grand slam finalist Anderson was encouraged by his remarkable return.

"It was a tough result but I think I can take away a lot of positives," he said.

"To have my first match and going straight up against Novak is obviously a little bit tough but I thought I did a good job after a nervous start."