Melbourne - When Roger Federer picks up his racket to face Aljaž Bedene in the Australian Open on Monday, he may be playing the match that determines whether he will defend his crown.
Federer also has to keep an eye on Rafael Nadal, a man who has proved himself capable of beating anyone who stands in his way.
The probability of Federer winning his 20th grand slam increased when he won the Hopman Cup, his first title of the year.
He and Belinda Bencic beat Germany’s Alexander Zverev and Angelique Kerber 4-3, 4-2 in the mixed doubles last week.
On the other hand, 2009 Australian Open winner Nadal hasn’t taken part in a competitive match since November, when he suffered a three-set loss to David Goffin in the ATP World Tour Finals in London.
Nadal also withdrew from the Brisbane International.
He was not in top form on Tuesday, when he lost to Richard Gasquet at the Kooyong Classic exhibition match.
But on Friday, he beat Austrian Dominic Thiem in a surprise exhibition match at Melbourne Park.
The 16-time grand slam champion will play his first match against Víctor Estrella Burgos on Monday morning.
The Spaniard had an incredible run last year, clinching his 10th French Open, his third US Open and ending the year at the top of the world rankings.
He was seeded No 1 on Thursday, but the world of tennis will be waiting to find out if his knee injury will get in the way of his grand slam ambitions.
World No 11 Kevin Anderson, who had one of his best seasons last year, beat world No 49 Kyle Edmund in the third round of last year’s French Open.
“It was a very close match. He’s a terrific player and has improved a lot. His forehand is very dangerous,” said the Johannesburg-born player.
Six-time Australian Open champion Novak Djokovic, who is seeded 14th, will take on world No 63 Donald Young.
The Serbian could win the match if his arm injury, which has kept him off the court since Wimbledon, doesn’t give him problems.
In the women’s division, unseeded players have won two of the past three grand slams – Jelena Ostapenko at the French Open and Sloane Stephens at the US Open.
The cycle might continue with Russian Maria Sharapova, who is unseeded in Melbourne.
Romanian Simona Halep is seeded first and Wimbledon champion Garbiñe Muguruza is seeded third, while Venus Williams is seeded fifth.