Novak Djokovic, who is eyeing a record 25th Grand Slam title, looks likely to need to beat either Jannik Sinner and Carlos Alcaraz or both at the business end of the Australian Open.
Sankar's father Subramanian encouraged him to drop out of the schooling system at an early age and pushed him to play in the upper age groups and senior circuits.
With Sunday's win, the world number one took his Grand Slam tally to 18, just two shy of Roger Federer and Rafael Nadal's men's record of 20.
Zverev has not lost to Wawrinka in two previous meetings but is not taking the 2014 Melbourne Park champion lightly.
Defending champion and world number one Novak Djokovic won his third-straight Australian Open crown, his ninth in total.
The Indian ace takes on Russian Grandmaster Peter Svidler in fifth round of the Corus International chess tournament.
Upbeat Venus ready to 'kill it' after loss to little sister
Serena Williams clinched a record 23rd grand slam title at the Australian Open on Saturday but spent most of the immediate aftermath talking about her older sister Venus.
American Stephens stayed calm and saw off an increasingly agitated Angelique Kerber in the winner-takes-all night match to complete round-robin play with a spotless 3-0 record after she wrapped up a 6-3, 6-3 victory against the German.
Serena Williams kept her bid for a calendar-year Grand Slam on track, powering past big sister Venus 6-2, 1-6, 6-3 on a steamy star-studded night at the US Open in New York, on Tuesday.