The world number one is bidding to become Australia's first women's singles champion in Melbourne since Chris O'Neil in 1978.
Top seed Rafael Nadal, 33, is celebrating becoming world number one in a third decade while Roger Federer, 38, is trying to defy the ageing process and stay ahead of his rivals with a 21st Grand Slam win.
Former number one Wozniacki announced in December that she would retire from tennis after Australian Open to focus on other things, including starting a family with husband and former NBA star David Lee.
The world number one became the first Aussie woman to lift a trophy on a home court since Jarmila Wolfe won Hobart in 2011.
The world number three faces Marie Bouzkova of the Czech Republic in her opener in Melbourne.
In the wake of the backlash, Australian Open organisers on Saturday unveiled a five-step air quality rating to determine when play should be halted.
Zverev had said that some of the other young players were "just better" than Kyrgios.
The Australian, whose matches have been 5,000-strong sellouts all week at Memorial Drive, will face Dayana Yastremska on Saturday for the title.
The 19-year-old Yastremska, ranked 24th, will play either Australian world number one Ashleigh Barty or American Danielle Collins.
The Spaniard is attempting to match Roger Federer's record 20 Grand Slam singles titles on his least favourite surface, having won in Melbourne just once, back in 2009.
The 22-year-old Japanese had a rollercoaster 2019, winning in Melbourne and topping the world rankings but then ploughing through three coaches before settling on Wim Fissette in December.
The reigning Wimbledon champion and former world number one dropped serve five times and was flattened in the second set by her opponent from Belarus.
There was only one break in each set of the evenly contested clash with Humbert winning 7-5, 6-4, clinching the victory with the Canadian's sixth double fault.
The world number 21 and Australia's top player pulled out of the Adelaide International with the same problem and has not been able to recover for his home Grand Slam.
The WTA Premier 5 tournament features eight of the world’s top-ten players.