Heckling, leg injury hound Djokovic as he advances in the Australian Open

Novak Djokovic defied rowdy fans and a leg injury to make it to the third round with a 6-1, 6-7 (5/7), 6-2, 6-0 win over French qualifier Enzo Couacaud, as he continues with his bid for a record-extending 10th Australian Open crown.

Thursday's victory was his 23rd straight win on the Melbourne Park centre court, as he steps up his quest for a 22nd Grand Slam crown.

But the Serbian champion admitted that he could not practise between matches and is worried that a hamstring injury could derail his bid.

In a colourful clash against an opponent ranked 191, Djokovic needed medical treatment and also had a major moment with the umpire, demanding that a drunken fan be thrown out.

"He's been drunk out of his mind from the first point, provoking me," he fumed in the fourth set.

"What are you going to do about it? Why don't you get him out of the stadium?"

Four fans, beer in hand, were later shown being escorted out.

Djokovic's dogged win set up a clash against Bulgaria's Grigor Dimitrov, who swept past another Serb, Laslo Djere, 6-3, 6-2, 6-0.

With three top 10 seeds, Rafael Nadal, Casper Ruud and Taylor Fritz, already out of the tournament, and world number one Carlos Alcaraz injured, Djokovic's route to another title has become easier.

That's if his left hamstring holds up.

"I am worried, I have reason to be worried," he said.

"My situation with my injury is not ideal... I have to take it day by day.

Djokovic aggravated the hamstring during his run to a 92nd tour-level title at the Adelaide International this month and his left thigh was again heavily strapped.

After racing through the first set, he went off for a medical timeout for treatment at 4-5 in the second set, with his movement hampered.

He returned to lose the tiebreak before recovering his poise.

'A lot happening'

"There was a lot happening tonight and Enzo deserves credit, he played some really great tennis, especially in the second set," added the 35-year-old, who is into the third round for a 15th time on his 18th visit to Australia.

In an early setback for Couacaud, he turned his ankle when stretching for a volley as he was broken to go 3-1 down in the opening set.

The Frenchman sought treatment but played on.

Fourth seed Djokovic exploited the injury, pushing him around the court, and broke again to stroll through the set in 41 minutes with Couacaud managing just three winners.

But Couacaud refused to give up.

The second set, dominated by long rallies, went with serve before Djokovic sought treatment at 4-5 after wincing on a backhand.

He returned with his thigh seemingly re-taped and Couacaud forced the set to a seesawing tiebreak, where he prevailed.

Djokovic found a second wind in the third set, banking an early break and never looking back.

With the injury seemingly forgotten, he raced through the next set after the rowdy fans were kicked out, and is now 7-0 for the season after winning in Adelaide.

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