MELBOURNE (Reuters) - Penpix of the top men's contenders at the 2019 Australian Open (prefix denotes seeding):
1-Novak Djokovic (Serbia)
World Ranking: 1
Born: May 22, 1987 (Age 31)
Grand Slam titles: 14 (Australian Open 2008, 2011, 2012, 2013, 2015, 2016; French Open 2016; Wimbledon 2011, 2014, 2015, 2018; U.S. Open 2011, 2015, 2018)
ATP career titles: 72
Best Australian Open performance: Winner (2008, 2011, 2012, 2013, 2015, 2016)
Biggest weapon: Back after an elbow injury, Djokovic has been unplayable at the last two slams. His trademark deep returns keep opponents pegged back and his fitness levels mean he thrives in adverse conditions where others wilt.
Biggest weakness: His serve is not the fastest and his break point conversion rate has dropped in the past year.
2-Rafa Nadal (Spain)
World Ranking: 2
Born: June 3, 1986 (Age 32)
Grand Slam titles: 17 (Australian Open 2009; French Open 2005, 2006, 2007, 2008, 2010, 2011, 2012, 2013, 2014, 2017, 2018; Wimbledon 2008, 2010; U.S. Open 2010, 2013, 2017)
ATP career titles: 80
Best Australian Open performance: Winner (2009)
Biggest weapon: Nadal's whipped topspin forehand is one of the most vicious shots in tennis.
Biggest weakness: Match fitness. Nadal's high energy style has taken a toll over the years and he retired during the U.S. Open semi-finals with tendonitis in his knee and followed that up by having ankle surgery in November.
3-Roger Federer (Switzerland)
World Ranking: 3
Born: Aug. 8, 1981 (Age 37)
Grand Slam titles: 20 (Australian Open 2004, 2006, 2007, 2010, 2017, 2018; French Open 2009; Wimbledon 2003, 2004, 2005, 2006, 2007, 2009, 2012, 2017; U.S. Open 2004, 2005, 2006, 2007, 2008)
ATP career titles: 99
Best Australian Open performance: Winner (2004, 2006, 2007, 2010, 2017, 2018)
Biggest weapon: The defending champion's serve-and-volley game allows him to conserve energy and finish points quickly. His vast experience and formidable shot selection let him switch tactics quickly, depending on the opponent and conditions.
Weakness: Even at 37, there are barely any chinks in Federer's armour but playing marathon five-setters in the Australian heat may prove to be his undoing, especially in the second week.
4-Alexander Zverev (Germany)
World ranking: 4
Born: April 20, 1997 (Age 21)
Grand Slam titles: 0
Career ATP titles: 10
Best Australian Open performance: Third round (2017, 2018)
Biggest weapon: Eight-times major winner Ivan Lendl is coaching Zverev with the aim of helping him overcome the big-games jitters that have dogged him in the past. The German strikes the ball crisply and has a delightful double-handed backhand.
Biggest weakness: Lack of experience and a disappointing record at Grand Slams, where the expectation has weighed him down.
Andy Murray (Britain)
World ranking: 230
Born: May 15, 1987 (Age: 31)
Grand Slam titles: 3 (Wimbledon 2013, 2016; U.S. Open 2012)
ATP career titles: 45
Best Australian Open performance: Runner-up (2010, 2011, 2013, 2015, 2016)
Biggest weapon: A hip injury has hampered the Scot's ability to cover the court and he will need to rely on precise shot-making and serving to be a contender. His double-handed backhand is still one of the best in the game.
Biggest weakness: Murray has failed to recapture his best form since undergoing hip surgery and may be exposed by the baseline hustlers in what could be his final tournament.
6-Marin Cilic (Croatia)
World ranking: 7
Born: Sept. 28, 1988 (Age: 30)
Grand Slam titles: 1 (U.S. Open 2014)
ATP career titles: 18
Best Australian Open performance: Runner-up (2018)
Biggest weapon: His booming serve gives him the ability to dictate play on any surface.
Biggest weakness: While he moves well for a big man, Cilic is prone to making mistakes in the longer rallies, especially if forced to cover ground.
8-Kei Nishikori (Japan)
World ranking: 9
Born: Dec. 29, 1989 (Age: 29)
Grand Slam titles: 0
ATP career titles: 12
Best Australian Open performance: Quarter-finals (2012, 2015, 2016)
Biggest weapon: Boundless energy. The Japanese number one is a classic counter-puncher, chasing down nearly everything his opponent sends over the net and using his fierce backhand to get himself out of jail.
Biggest weakness: Not enough power. Nishikori is often outmuscled by the game's biggest hitters and his serve lacks bite.
Nick Kyrgios (Australia)
World ranking: 51
Born: April 27, 1995 (Age 23)
Grand Slam titles: 0
Career ATP titles: 4
Best Australian Open performance: Quarter-finals (2015)
Biggest weapon: Cannonball serves that can blow opponents away and incredible athletic ability that makes him solid on both wings. Kyrgios is a force to be reckoned with if he can keep it together.
Biggest weakness: The mercurial Australian is a ticking time bomb, struggling for consistency on the biggest stage, and has been accused of lacking the stomach for a fight when things are not going his way.
(Compiled by Rohith Nair in Bengaluru, editing by Nick Mulvenney)