Serving disaster cruels Joker in crazy first set

Novak Djokovic showed worrying signs of the scars left from his troublesome elbow with a serving disaster in the first set of his fourth round Australian Open clash.

The six-time champion came up against rising Korean star Hyeon Chung at Melbourne Park on Monday night but his biggest enemy was his own serve early on.

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The 14th seed's horror start began with two successive double faults that saw him drop his first service game against the World No.58.

Djokovic's new serving technique was causing him problems. Pic: Getty

Djokovic then followed that up with two more at the start of his next game to virtually hand the 21-year-old Korean a 4-0 lead in the opening set.

Channel 7 commentator Jim Courier pointed out that Djokovic took six months out from the game last year due to a troublesome elbow.

"At Wiimbledon last year he retired mid-tournament and that was really the first time that he'd let on he’d been carrying an elbow injury," Courier explained.

"So he went away from the Tour and he has changed his service motion, abbreviated it ala Pat Rafter on his take-back. It's much shorter than it was."

Whatever the change was clearly wasn't working for the Serb but he did manage to hold his next service game before breaking the Korean to get himself back in the contest.

Incredibly though, the 12-time major winner showed his famous fighting qualities to force his way in a tie-breaker with the Korean young gun.

However, it was the 21-year-old who managed to wrestle the momentum back to win it 7-4.

Further drama ensued between sets as Djokovic then called for a medical timeout to get treatment from a trainer on his elbow.

The winner of Monday night's other match between Dominic Thiem and Tennys Sandgren will face either Djokovic or Chung in the quarter-finals.