Novak Djokovic is targeting a record-extending ninth title at Melbourne Park with Rafael Nadal and Dominic Thiem shaping as his biggest challengers while six-time champion Roger Federer is sidelined for the first Grand Slam tennis tournament of the year.
Here are five men's singles players to watch when the Australian Open starts Monday after a three-week delay because of the coronavirus:
Novak Djokovic
The world number one has a chance of ending 2021 as the most successful men's Grand Slam player in history, and has grown used to starting his year with a bang at his favourite major.
The Serb has won a record eight times in Melbourne, the scene of his maiden Grand Slam triumph in 2008, and is unbeaten on the famous blue courts since his shock last-16 defeat to South Korea's Hyeon Chung in 2018.
With 17 Grand Slam singles titles, Djokovic is three behind the all-time record of 20 shared by Rafael Nadal and Roger Federer.
The 33-year-old's peerless Australian Open record is tempered slightly by his mixed reputation among fans, who often measure him alongside the ever-popular Federer -- absent this year after two rounds of knee surgery -- and Nadal.
Djokovic has also been guilty of some missteps during the pandemic, including hosting a super-spreader tournament series in the Balkans and asking for special privileges for players quarantining in Australia.
Rafael Nadal
Victory this week would take Nadal, 34, past Federer on the men's all-time Grand Slam titles list, a task that has been eased by the Swiss great's withdrawal through injury.
However, the 13-time French Open winner has often laboured in vain in Melbourne, despite reaching five finals, and his lone triumph in 2009 now seems to belong to another era.
The king of clay is not usually at his best on hardcourts, although his 20 major titles include four at the US Open. He is also nursing a sore back that kept him out of the ATP Cup.
But Nadal can hardly have any more motivation than becoming the first man to reach 21 Grand Slam singles titles, while also putting more daylight between him and Djokovic.
Dominic Thiem
Thiem was a narrow loser to Djokovic in the last Melbourne final, but this year he arrives as a Grand Slam champion for the first time after his breakthrough win at the US Open.
The Austrian baseliner overcame Germany's Alexander Zverev in five sets at Flushing Meadows to get his name finally on a major trophy in his fourth Grand Slam final.
A first Grand Slam victory had long looked inevitable for the 27-year-old, who led Djokovic two sets to one in last year's Australian final before the Serb fought back to win in five.
Third-ranked Thiem also reached the title match of the ATP Finals in November and he will expect to continue his steady upward trajectory this year.
However, Thiem is in Melbourne without his coach Nicolas Massu, who tested positive for the coronavirus, and is instead working under his father, Wolfgang, Austria's ATP Cup captain.
Daniil Medvedev
Thiem's victory in New York made him the first new Grand Slam winner in six years and Medvedev, who led Russia to ATP Cup success on Sunday, is among those hoping it's another sign the Big Three era is fading.
The 24-year-old Russian is another player who has been knocking on the door. He reached the 2019 US Open final -- losing in five sets to Nadal -- and the last four in New York in 2020.
Medvedev went on a tear at the end of last season, winning 10 matches in a row and lifting the Paris Masters and ATP Finals trophies.
After beating Djokovic and Nadal in London, and edging a gripping final against Thiem, Medvedev became the first player to account for all of the world's top three at the season finale.
Medvedev, who had a tour-leading 59 victories in 2019, has won all nine of his ATP titles on hardcourts, and will now want to improve on his fourth-round showings on his last two visits to Melbourne Park.
Alexander Zverev
Reaching a first Grand Slam final at the US Open was a big step forward for Zverev, but the German will have a bigger prize in his sights in Melbourne.
Zverev came desperately close to winning his first major in New York in September, when Thiem needed a fifth-set tiebreak to subdue his long-time friend and sparring partner.
Thiem was also Zverev's nemesis at last year's Australian Open, when the German threw away a one-set lead to lose in four in the semi-finals.
The tall, blond Zverev arrives with baggage this year, after allegations of domestic abuse by a former girlfriend. He also split recently with coach David Ferrer.
However, the 23-year-old showed he could deal with off-court distractions last year, when he shrugged off a running row with Australia's Nick Kyrgios to reach the last four.
PAST WINNERS
This century's men's singles champions at the Australian Open, which is due to start in Melbourne on February 8 after being delayed three weeks by coronavirus restrictions:
2020 - Novak Djokovic (SRB)
2019 - Novak Djokovic (SRB)
2018 - Roger Federer (SUI)
2017 - Roger Federer (SUI)
2016 - Novak Djokovic (SRB)
2015 - Novak Djokovic (SRB)
2014 - Stan Wawrinka (SUI)
2013 - Novak Djokovic (SRB)
2012 - Novak Djokovic (SRB)
2011 - Novak Djokovic (SRB)
2010 - Roger Federer (SUI)
2009 - Rafael Nadal (ESP)
2008 - Novak Djokovic (SRB)
2007 - Roger Federer (SUI)
2006 - Roger Federer (SUI)
2005 - Marat Safin (RUS)
2004 - Roger Federer (SUI)
2003 - Andre Agassi (USA)
2002 - Thomas Johansson (SWE)
2001 - Andre Agassi (USA)
2000 - Andre Agassi (USA)
DRAW
The draw for the Australian Open men's singles in Melbourne starting Monday (x denotes seeding):
Novak Djokovic (SRB x1) v Jeremy Chardy (FRA)
Frances Tiafoe (USA) v Stefano Travaglia (ITA)
Reilly Opelka (USA) v Lu Yen-hsun (TPE)
Albert Ramos-Vinolas (ESP) v Taylor Fritz (USA
Stan Wawrinka (SUI x17) v Pedro Sousa (POR)
Martin Fucsovics (HUN) v Marc Polmans AUS
Corentin Moutet (FRA) v John Millman (AUS)
Federico Coria (ARG) v Milos Raonic (CAN x14)
Gael Monfils (FRA x10) v Emil Ruusuvuori (FIN)
Yoshihito Nishioka (JPN) v Pedro Martinez (ESP)
Aljaz Bedene (SLO) v Alexander Bublik (KAZ)
Sergiy Stakhovsky (UKR) v Dusan Lajovic (SRB x23)
Adrian Mannarino (FRA x32) v Dennis Novak (AUT)
Moimir Kecmanovic (SRB) v Kamil Majchrzak (POL)
Taro Daniel (JPN) v Maxime Cressy (USA)
Marcos Giron (USA) v Alexander Zverev (GER x6)
Dominic Thiem (AUT x3) v Mikhail Kukushkin (KAZ)
Dominik Koepfer (GER) v Hugo Dellien (BOL)
Frederico Ferreira Silva (POR) v Nick Kyrgios (AUS)
Yasutaka Uchiyama (JPN) v Ugo Humbert (FRA x29)
Grigor Dimitrov (BUL x18) v Marin Cilic (CRO)
Alex Bolt (AUS) v Norbert Gombos (SVK)
Kimmer Coppejans (BEL) v Jiri Vesely (CZE)
Kei Nishikori (JPN) v Pablo Carreno Busta (ESP x15)
Denis Shapovalov (CAN x11) v Jannik Sinner (ITA)
Yuichi Sugita (JPN) v Bernard Tomic (AUS)
Damir Dzumhur (BIH) v James Duckworth (AUS)
Cedrik-Marcel Stebe (GER) v Felix Auger-Aliassime (CAN x20)
Benoit Paire (FRA x 25) v Egor Gerasimov (BLR)
Gianluca Mager (ITA) v Aslan Karatsev (RUS)
Federico Delbonis (ARG) v Juan Ignacio Londero (ARG)
Elias Ymer (SWE) v Diego Schwartzman (ARG x8)
Andrey Rublev (RUS x7) v Yannick Hanfmann (GER)
Thiago Monteiro (BRA) v Andrej Martin (SVK)
Li Tu (AUS) v Feliciano Lopez (ESP)
Sam Querrey (USA) v Lorenzo Sonego (ITA x31)
Casper Ruud (NOR x24) v Jordan Thompson (AUS)
Nikoloz Basilashvili (GEO) v Tommy Paul (USA)
Christopher O'Connell (AUS) v Jan-Lennard Struff (GER)
Radu Albot (MDA) v Roberto Bautista Agut (ESP x12)
David Goffin (BEL x13) v Alexei Popyrin (AUS)
Lloyd HARRIS (RSA) v Mikael Torpegaard (DEN)
Mackenzie McDonald (USA) v Marco Cecchinato (ITA)
Guido Pella (ARG) v Borna Coric (CRO x22)
Filip Krajinovic (SRB x28) v Robin Haase (NED)
Pablo Andujar (ESP) v Quentin Halys (FRA)
Roberto Carballes Baena (ESP) v Attila Balazs (HUN)
Vasek Pospisil (CAN) v Daniil Medvedev (RUS x4)
Stefanos Tsitsipas (GRE x5) v Gilles Simon (FRA)
Thanasi Kokkinakis (AUS) v Kwon Soon-woo (KOR)
Botic Van de Zandshhulp (NED) v Carlos Alcaraz (ESP)
Mikael Ymer (SWE) v Hubert Hurkacz (POL x26)
Karen Khachanov (RUS x19) v Aleksander Vukic (AUS)
Ricardas Berankis (LTU) v Sumit Nagal (IND)
Tomas Machac (CZE) v Mario Vilella Martinez (ESP)
Kevin Anderson (RSA) v Matteo Berrettini (ITA x9)
Fabio Fognini (ITA x16) v Pierre-Hugues Herbert (FRA)
Henri Laaksonen (SUI) v Salvatore Caruso (ITA)
Pablo Cuevas (URU) v Andreas Seppi (ITA)
Tennys Sandgren (USA) v Alex De Minaur (AUS x21)
Dan Evans (GBR x30) v Cameron Norrie (GBR)
Ilya Ivashka (BLR) v Roman Safiullin (RUS)
Michael Mmoh (USA) v Victor Troicki (SRB)
Laslo Djere (SRB) v Rafael Nadal (ESP x2)