Former world No. 1 Novak Djokovic and three-time major champion Stan Wawrinka could pose a serious threat to Alexander Zverev's hopes of mounting a breakout Grand Slam campaign at the Australian Open, where Rafael Nadal and Roger Federer can be confident of advancing to the latter stages.
Zverev, 20, won five tournaments last year, including Masters 1000 events in Rome and Montreal, to announce himself as a force to be reckoned with.
The German is seeded fourth at Melbourne Park but has never experienced a quarterfinal, or beyond, at a major.
He could have to beat his brother Mischa, six-time champion Djokovic and then 2014 winner Wawrinka if he is even to reach the last four, where a semifinal against reigning champion Federer could await.
Djokovic and Wawrinka, though, are yet to demonstrate that they have fully recovered from the elbow and knee injuries, respectively, that have sidelined the pair since August.
World No. 1 Nadal, meanwhile, has been granted what appears to be a relatively simple route into the latter stages of the tournament, but only if last year's beaten finalist can prove his fitness following recent knee problems of his own.
Here, we assess the chances of the favorites, outsiders and dark horses following the draw for the first slam of 2018…
PROJECTED QUARTERFINAL TIES
Rafael Nadal (1) vs. Marin Cilic (6)
Nadal's portion of the draw holds few major concerns for the 16-time Slam winner, whose first potential seeded opponent is world No. 28 Damir Dzumhur.
After that, John Isner (16) or Diego Schwartzman (24) could meet the Spaniard in the round of 16.
Cilic, the 2014 U.S. Open winner and last year's beaten Wimbledon finalist, will be expected to face Nadal in the last eight, with Pablo Carreno Busta (10) and Pablo Cuevas (31) also lurking, as well as Gilles Muller (23) — Nadal's conqueror at Wimbledon last year.
Unseeded threat: Gilles Simon.
Grigor Dimitrov (3) vs. Jack Sock (8)
Dimitrov has been tipped to challenge in Melbourne after winning last year's ATP Finals in London, but there are two immediate threats to the Bulgarian in the form of mercurial home hope Nick Kyrgios (17) and entertaining Frenchman Jo-Wilfried Tsonga (15).
Surprise Paris Masters winner Jack Sock may have to overcome Kevin Anderson (11) or Lucas Pouille (18), as well as Philipp Kohlschreiber (27) if he is to reach the quarterfinals.
Unseeded threats: David Ferrer, Denis Shapovalov.
Dominic Thiem (5) vs. Alexander Zverev (4)
Zverev is considered the heir apparent to the ATP's aging superstars, but his hopes of advancing deep into this Slam could come under an early threat from two dangerous floaters in the most hotly contested quarter of the draw.
Brother Mischa (32) and Albert Ramos-Vinolas (21) should not unduly trouble the 20-year-old, but six-time champion Djokovic, seeded 14th after his lengthy absence from the tour, could yet blow his portion of the draw wide open should he prove his fitness.
Assuming he emerges from a likely early meeting with Adrian Mannarino (26), fifth seed Dominic Thiem may come under threat from Wawrinka (9). The 2014 winner has also been sidelined for four months following knee surgery, but the Swiss could prove too strong for Roberto Bautista Agut (20).
Unseeded threat: Gael Monfils.
David Goffin (7) vs. Roger Federer (2)
Goffin enjoyed a strong finish to 2017, reaching the decider of the ATP Finals and the Davis Cup final with Belgium. The seventh seed may have to deal with any of Fabio Fognini (25), Tomas Berdych (19) or Juan Martin del Potro (12) if he is to get to the last eight in Melbourne.
Awaiting him there should be holder Federer (2), whose first scheduled seeded opponent may be Richard Gasquet (29). Sam Querrey (13) or Milos Raonic (22) are likely to find themselves in the firing line of the Swiss great during the round of 16.
Unseeded threat: Karen Khachanov.