Novak Djokovic of Serbia celebrates after defeating Carlos Alcaraz of Spain in their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia. (AP )

MELBOURNE, Australia, Jan 21, (AP): Novak Djokovic refused to let anything stop his pursuit of a record 25th Grand Slam trophy in the Australian Open quarterfinals. Not no problem with his left leg. Not an early deficit. And not the kid across the net, Carlos Alcaraz, who was making things difficult and eyeing his bit of history.

Djokovic overcame it all, just as he has so often along the way to so many triumphs, moving into the semifinals at Melbourne Park for the 12th time with a 4-6, 6-4, 6-3, 6-4 victory over Alcaraz in a scintillating showdown Tuesday night between a pair of stars born 16 years apart and at opposite ends of their careers.

The action was non-stop, the shot-making brilliant, even as the encounter stretched on for more than 3 1/2 hours and nearly to 1 a.m. - never more so, perhaps, than when Alcaraz saved a break point in the fourth set. The 33-stroke exchange was the longest of the evening, and when it ended with Djokovic sailing a forehand long, the capacity crowd at Rod Laver Arena went wild. Djokovic reached for his bothersome leg and yelled toward his entourage; Alcaraz, his chest heaving, leaned on a towel box and grinned.

Turned out that only delayed the final result.

When the match ended, Djokovic yelled toward his team's box, before giving his coach, Andy Murray, a hug. Then Djokovic applauded for No. 3 seed Alcaraz as he left the court.