An emotional Andy Murray kicks off his Australian Open campaign against Spaniard Roberto Agut in the night session at Melbourne Park on Monday.
It is what could well be the final match of the Scot’s glittering career.
Hip surgery a year ago has left the three-times Grand Slam champion in severe pain.
The 31-year-old said last week that the year’s first Grand Slam could be his last tournament.
Murray has never lost in three meetings with Agut and last beat the 22nd seed in the Shanghai Masters final in 2016.
It was however when the Scot was at his peak, having just won his second Wimbledon title and Olympic gold in Rio.
Both players’ fortunes have changed since they last faced each other over the net.
Agut is coming off an impressive run in Doha, where he beat Stan Wawrinka, Novak Djokovic and Tomas Berdych en route to winning the title.
Murray, in contrast, is ranked 230th in the world and was beaten in straight sets by Russia’s Daniil Medvedev at the Brisbane International warm-up.
The Scot said his troublesome hip had stacked the odds against him.
“I know most likely I’m going to lose in the first round,” added Murray, who has finished runner-up in Melbourne five times but never won the title.
“If it is my last match, I want to try and enjoy it.”
An hour after Murray walks on to the Melbourne Arena, defending women’s champion Caroline Wozniacki will take on unseeded Belgian Alison Van Uytvanck under the lights on the tournament’s main showcourt.
Wozniacki will be followed by men’s champion Roger Federer, whose quest for a third Australian Open title in a row begins with an eighth career meeting with Uzbekistan’s Denis Istomin.
Federer, who has never lost to Istomin before, will be grateful the match is in the evening.
It allowed the Swiss veteran to avoid the worst of the heat on what promises to be a scorching day.
Temperatures are expected to soar to about 36-37 Celsius (96-99 Fahrenheit) in Melbourne on Monday, with high humidity set to make it the hottest day of the week.
Organisers have updated the tournament’s extreme heat policy, and Tennis Australia’s new “Heat Stress Scale” is likely to be pressed into action from the start.
First to feel the heat will be 2008 champion Maria Sharapova, who kicks things off on Rod Laver against unseeded Briton Harriet Dart.
Second seed Rafa Nadal will battle the worst of the conditions when he takes on Australian wild card and world number 238 James Duckworth in the second match on Rod Laver.
Nadal, who pulled out of the Brisbane International with a thigh strain, has shrugged off concerns his battle-scarred body may not be able to handle the strain.
There is going to be two weeks of top-level tennis, but doubts remain whether he will be able to stand the strain.
The Spaniard recently had ankle surgery and has twice lost to wild cards at a major before.
The first time was at the hands of James Blake in the 2005 U.S. Open and then to Nick Kyrgios at Wimbledon in 2014.
Australian teen Alex de Minaur, who won his first career title at the Sydney International on Saturday, is in action against Portugal’s Pedro Sousa on Margaret Court Arena.
World number 15 Ashleigh Barty faces Thailand’s Luksika Kumkhum on Margaret Court in the first match of the evening session.
Barty is carrying home hopes in the women’s draw and was a losing finalist in Sydney.