World No 7 is not fully fit but has mental edge in semi-final over opponent who has repeatedly cowered under pressure

Even before he had undergone medical tests, defined the nature of his physical ailment and planned for his recovery, Novak Djokovic knew what was in store for him in the days after his remarkable quarter-final victory over Carlos Alcaraz on Tuesday, which he pulled off despite struggling with left thigh pain.

Just as he suggested post-match, Djokovic has not been present on the practice courts at Melbourne Park for Friday’s semi-final with Alexander Zverev. After being absent from the practice schedule on Wednesday, his scheduled 2pm training session had been wiped from the list on Thursday morning.

• American victorious with 5-7, 6-1, 7-6 (8) win
• Advances to her second grand slam final

As Madison Keys stared down a match point in the final set of one of the most extraordinary matches of her career, she had ample reason to slump her shoulders and lament the crushing defeat that seemed to be imminent.

From a set down, Keys had rallied brilliantly, dragging herself back into contention with some of the most destructive, daring ­shotmaking exhibited all tournament. In the breathless final set that followed, when she was so often close to ­losing, the 19th seed continually found the courage and heart to force her way back into the match.

The 37-year-old showed killer instinct against younger rival, a willingness to go to hell and back in pursuit of glory

In the most recent late-night exhibition of his insatiable resilience and desire, as he again belied his ageing body to deliver another legendary performance, one of the most significant moments of Novak Djokovic’s quarter-final defeat of Carlos Alcaraz at the Australian Open came as the Serb clung on desperately to his frail momentum.

With a set point on his serve at 5-3 in the third set, Djokovic was hurled around the court by Alcaraz, chasing down a drop shot before stumbling back to the baseline in pursuit of a lob. The frantic point – and set – ended with Djokovic slipping an angled backhand passing shot by Alcaraz before cupping his hands to his ear while the Rod Laver Arena erupted.