Novak Djokovic brushed aside Albert Ramos-Vinolas to reach the fourth round of the Australian Open, but the Serbian's fitness is a cause for concern as he struggled with a hip injury.
The six-time champion at Melbourne Park only returned to action at the start of this tournament due to an elbow problem that has troubled him since Wimbledon, and a new injury concern threatens to derail his 2018 title bid.
Despite the noticeable problem on his left side, Djokovic was able to battle through the pain barrier to see off Ramos-Vinolas in two hours and 21 minutes, the former world number one winning 6-2 6-3 6-3.
Early on it looked like Ramos-Vinolas might give Djokovic a run for his money on Margaret Court Arena with some powerful shots from the baseline, but when he had openings the 21st seed failed to take them.
Twice in his first three service games Djokovic had to save break points, but after taking a 3-2 lead he never looked back and he reeled off the next three games to take the first set, his backhand and touch at the net showing promising signs.
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Djokovic regularly used a disguised drop shot to break up the baseline battle, toying with Ramos-Vinolas at times.
His right elbow was strapped throughout the encounter but did not appear to hamper the 30-year-old, however he needed a medical timeout for attention on his left hip in the second set.
Djokovic returned after being treated but looked hampered by the issue and was noticeably grabbing at his hip, and limping after most points - particularly when forced to run by his Spanish opponent.
Yet somehow, he managed to find a new gear, spraying shots to all corners from the baseline as he marched towards a two-set lead.
That was Djokovic's 12th set in a row against Ramos-Vinolas and it quickly became 13 as he broke in game three of the third set, the Serbian benefitting from his opponent's misplaced forehand that clipped the net and dropped wide.
Djokovic began to move a little freer as the match wore on and he was able to secure a fourth-round clash with rising star Hyeon Chung with a fifth break of the match courtesy of a Ramos-Vinolas double fault.
Djokovic  bt Ramos Vinolas  6-2 6-3 6-3
Djokovic - 37/42
Ramos-Vinolas - 21/34
Djokovic - 2/3
Ramos-Vinolas - 3/3
BREAK POINTS WON
Djokovic - 5/12
Ramos-Vinolas - 0/6
FIRST SERVE PERCENTAGE
Djokovic - 63
Ramos-Vinolas - 59
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Djokovic - 80/50
Ramos-Vinolas - 60/51
Djokovic - 102
Ramos-Vinolas - 81