Novak Djokovic goes through to the final 16 of the Australian Open, despite worries after picking up a knee injury. But as the Serbian celebrates his third round win, all eyes have been on his serving.The 12-time Grand Slam Singles winner has been suffering from a long-term elbow problem and has recently returned to playing after a six-month resting period. But as the Australian Open continues, it appears his elbow is causing more problems.One thing we've noticed is Djokovic wearing an arm/elbow band on his right arm, but something else has been noticed too.It appears that he's also changed his serving motion. Many have been watching closely and comparing the former world no.1's serve with older footage.The 30-year follows his ball toss straight up with his racquet arm, rather than his older technique, where his racquet arm would swing down before following up to meet with the ball.The more compact technique might be helping with his ongoing elbow problems, but as a tennis pro, it isn't an easy task learning a new serving technique.The Serbian did talk before the Australian Open tournament about how he had made some small changes to his serve and was looking forward to 'unveiling the new motion' and how his serving motion hasn't changed completely.Djokovic commented saying: "It's not entirely different, but at the beginning, even those small tweaks and changes have made a lot of difference mentally. I needed time to kind of get used to that change, understand whether that's good or not good for me."

Video compares Djokovic's serving motions

Well, whilst he's been focusing on the Australian Open, many others have stayed focussed on his serving.

In a comparison video posted by Ilya Ryvlin‏ on Twitter, many fans were quick to comment on the differences in the 'old Djokovic serving' and 'new Djokovic serving'.

The footage compares Djokovic's new serve with that from a Wimbledon match.

One said: "He’s not rotating his elbow and he’s getting to the impact point quicker! I’m eager to see how this will develop throughout the season"

Another commented: "...I am always in favour of quick/simple moves where you use more speed than sheer power."

One thing that is clear is Djokovic isn't going to be at '100 per cent' anytime soon and that he won't be expecting everything out of the Australian Open.

“I had some incredible memories of Melbourne Park in the last decade of my career,” Djokovic said.

“Obviously that comes back every time I land in Melbourne and every time I come out on these courts, but obviously I have to be more humble this time with my expectations because I haven’t
played for six months. But I’m very pleased with where my game is at the moment.”

Despite problems with his elbow, the new serving technique seems to be working for the Serbian as he is now through to the final 16 after a win over Albert Ramos-Vinolas.

Djokovic will now face Hyeon Chung in the fourth round of the competition.