Novak Djokovic continued his charge towards a 10th Australian Open title after winning against Grigor Dimitrov to reach the fourth round on Saturday, but fears about his injured left hamstring grew.
He bagged a superb 7-6(7) 6-3 6-4 victory against his Bulgarian opponent.
The Serbian, who is eyeing a 22nd major to match Rafa Nadal, looked uncertain in his movement in a roller-coaster opening set where he began with a break, squandered three set points at 5-3 and dropped serve late on before edging a thrilling tiebreak.
A heavily-strapped but more aggressive Djokovic emerged from a medical timeout and built pressure with his relentless returns from the back, going up 4-2 as 27th seed Dimitrov hit the net to surrender his serve and went on to wrap up the second set.
A half-fit Djokovic can still be a handful for most players, but the fourth seed looked a little more certain of his mobility in the third set and a double break to start helped him subdue the error-prone Dimitrov, who failed to make a late comeback.
FIFA President Gianni Infantino proposed an outside review of how the governing body makes major decisions on Monday, acknowledging in a letter to members that its handling of a now-abandoned investment plan had caused concern.
Captain Marquinhos has snatched the winner as champions Paris St Germain won 2-1 at troubled Olympique de Marseille in Ligue 1 on Sunday, condemning the hosts to a fifth successive loss and a spot in the relegation zone.
Anders Dreyer has scored his 10th and 11th goals on either side of halftime and visiting San Diego FC earned a 2-2 draw against Lionel Messi and defending MLS Cup champions Inter Miami on Sunday night.
Manchester City head into the first international break three points clear at the top of the Premier League after Antoine Semenyo's double sealed an enthralling 5-3 home win over Sunderland, for whom Brian Brobbey grabbed a hat-trick, on Sunday.