Players to watch at the Australian Open

Stan Wawrinka upset the odds to win his maiden Grand Slam in Melbourne last year, but big guns Rafael Nadal and Novak Djokovic struck back by winning at Roland Garros and Wimbledon respectively.

Marin Cilic then proved too strong for Kei Nishikori at the US Open in a final that no one predicted.

The championship match at Flushing Meadows was remarkably the first not to feature the 'Big Four' of Roger Federer, Nadal, Djokovic or Britain's Andy Murray since the Melbourne final in 2005, when Marat Safin beat Lleyton Hewitt.

Given the fact that those four players have shared an incredible 41 of the last 46 slams between them, Wawrinka and Cilic's achievement last year is all the more impressive.

Gaston Gaudio (French Open 2004), Safin (Australian Open 2005), Juan Martin Del Potro (US Open 2009), 'Stan The Man' and Croatia's Cilic last year are the exceptions.

Is there anybody in today's game that could possibly upset the odds in the sweltering heat of Melbourne at the opening major of the year?

Here, we look at five players who have the potential to cause an upset or two at the Australian Open...

Kei Nishikori (Sky Bet odds: 14/1)

Japan's rising son was named ATP Newcomer of Year in 2008 and has since gone from strength to strength on the tour – climbing to a career-high fifth in the world after reaching his maiden Grand Slam final in 'The Big Apple'. As a teenager, Nishikori moved to the USA without knowing a word of English to practice the arts of tennis at the Bollettieri Acadamey in Florida. It wasn't long before he became the youngest player to win an ATP title since Lleyton Hewitt at the age of 16 years, 10 months, 18 days in Adelaide. By the end of the year he became the first Japanese player to finish in the Top 100 since Shuzuo Matsuoka in 1995. In 2011, he compiled the best set of results of his career, finishing as world No 25 after reaching two ATP finals in Houston and Basel.

Two years later he won his second career title on home soil in Tokyo, but injury held Nishikori back from making further progression after suffering problems with his elbow and abdominal muscle. Nishikori enlisted the help of tennis great Michael Chang as he looked to break into the Top 10 in 2014. And although his left knee troubled him early in the season, in February he won his third title in Memphis.

The 25-year-old was improving fast and recorded just his fourth win over a top-five opponent when he shocked Roger Federer in Madrid with a three-set win. He became the first Japanese man to reach the Wimbledon third round for 17 years in 2013 – emulating Matsuoka's run to the last 32 back in 1995 – and reached the same stage at the All England Club in 2014. Nishikori very nearly fulfilled his potential in New York as he overcame close rival Milos Raonic in an epic last-16 battle before seeing off Stan Wawrinka and then shocking world No 1 Novak Djokovic in the semi-finals. However, the Japanese trailblazer ran out of steam in the final against Marin Cilic and lost in straight sets.

Milos Raonic (Sky Bet odds: 40/1)

Born in Podgorica, Montenegro, Raonic moved to Canada with his family at the age of three and started playing the game at the age of eight. He has since grown into a 6ft 5in powerhouse of a sportsman. The 24-year-old has won the SAP Open title in San Jose three years in a row, but his form last season has been nothing short of exceptional. He is known for his huge serves and bludgeoning groundstrokes but admitted that he needed to start playing with more 'grit' last season. It seems to have worked too!

He reached the quarter-finals at Indian Wells, Miami, Monte Carlo and Portugal this year before losing out to Novak Djokovic in his first Masters semi-final in Rome. The Canadian has improved his movement and overall game thanks in large part to the services of former top three player Ivan Ljubicic. "Being coached by Ivan will really offer a new dimension to my game," said Raonic. "He brings such a vast knowledge of the game and his recent experience on Tour is a major plus for my development. We both come from aggressive styles of play so he can definitely understand the mentality I have on court and areas where I can improve."

Raonic went down to a straight-sets defeat to Roger Federer in his first Grand Slam semi-final at Wimbledon, although he rebounded in style by beating his compatriot Vasek Pospisil in the first all-Canadian tournament final in ATP history in Washington after which he climbed to a career-high No 6. He warmed up for this year's Grand Slam by finishing as runner-up to Federer in Brisbane, but must be regarded as a good outside bet to go deep into the tournament.

Grigor Dimitrov (Sky Bet odds: 22/1)

Last year was a breakthrough year for the Bulgarian prodigy, who reached the Wimbledon semi-finals just weeks after claiming his first grass court title at Queen's Club. He earned the tag 'Baby Federer' following his triumph at the All England Club and the US Open as a junior. The athletic and agile 23-year-old, who has reached a career-high ranking of eight, stretched Rafael Nadal at the Australian Open quarter-finals in January, taking the Spaniard to four sets.

It's now common knowledge that he is dating one of the richest and most glamorous women in tennis, Maria Sharapova, but despite all the media spotlight he is making an impact on the ATP circuit, becoming the first Bulgarian to win a World Tour title in the Open Era in Stockholm and then capturing the Acapulco crown in March and Bucharest title in May.

The physical weaknesses that stopped Dimitrov making the most of his huge talent have gone, and there is now a belief that he belongs with the very best. "I have worked really hard to start winning titles," he said in Bucharest. "I have put in enough effort, time and sacrifices to get here." The cultured right-hander, who is mentored by eccentric Australian coach Roger Rasheed, demolished Andy Murray in the Wimbledon quarter-finals before bowing out to Novak Djokovic in the last four. "I played against a future star, he is already a top player with quality shots and a great touch," said the Serb following his 6-4 3-6 7-6 (7-2) 7-6 (9-7) win on Centre Court.

At the US Open he suffered a last-16 defeat to flamboyant Frenchman Gael Monfils and he began this year by reaching the last four in Brisbane before losing to that man Federer for the third time in his career. His country feel they may have found a new hero to follow in the footsteps of Hristo Stoichkov – a former footballer who led the national side to the 1994 World Cup semi-final. And they may just be right because this could be the slam where the Haskovo-born player steps up and reaches a major final for the first time.

Ernests Gulbis (Sky Bet odds: 125/1)

Gulbis comes from wealthy stock with his book-collecting parents naming him after Ernest Hemingway. His father is a wealthy investment banker while his mother is an actress. He attended the Niki Pilic academy in Munich as a teenager and became good friends with Novak Djokovic. Gulbis described his belated dedication to tennis as "jumping on the last train" and just a few years ago, after reaching the semis in Rome, he immediately flew home to Riga, arriving at 1am before going straight to a nightclub.

He was also reported to have blown £43,000 in a casino, but the tennis tearaway has put his party days behind him and is spending more time on the practice courts, and it seems to be paying off. He discovered his best form in the past 18 months and climbing to a career-high 10 in June. He claimed the biggest win of his career as he stunned Roger Federer to reach the French Open quarter-finals before bowing out to eventual finalist Novak Djokovic. The player, who was known for his huge serve and also used to smash up to 70 rackets a year, secured his third ATP Tour career title at Delray Beach and his first since 2011 before triumphing in the St Petersburg Open in 2013.

He landed his fifth career title in Marseille when he upset second seed and defending champion Jo-Wilfried Tsonga to the Open 13 crown. Afterwards, he outlined his long-term ambitions in the game. "My long-term goal in tennis isn't to be top 20. It's to be No 1. Anything less than that wouldn't make me fully satisfied. I don't want to get to 30 years old, look back on my career and say I didn't make something of it. I think (the top players) feel threatened by my game, because they know if I serve well and I'm aggressive, then it's tough to play against me. I don't feel I'm in the same league as the (top four) yet, I need to prove it. Game-wise, I think that I can be."

He won his sixth career title and first on clay when he captured the Nice crown – just a day before the start of the French Open – but suffered a second round exit to last year's Federer-slayer Sergiy Stakhovsky at Wimbledon. His form dipped ahead of the US Open where he lost out to young Austrian prodigy Dominic Thiem in the second-round. He will hope to regain some confidence when he heads down under for the opening slam of the year.

David Goffin (Sky Bet odds: 125/1)

The Belgian youngster is considered to be one of the sport's most promising stars but drifted off the radar after making headlines at the French Open. He was born in Rocourt, which is the same town as seven-time Grand Slam champion Justine Henin, and was taught the game by his father, Michel from the age of six. Clay courts are his forte and he surprised everybody by reaching the fourth round at Roland Garros in 2012 after entering the tournament's main draw as a lucky loser.

He went on to beat Radek Stepanek in five sets before dispatching Arnaud Clement and Lukasz Kubot. Goffin became the first lucky loser to reach the fourth round of a major championship since fellow Belgian Dick Norman at Wimbledon in 1995, but then faced his childhood idol Roger Federer. The Swiss master won in four sets that day, but spoke positively about his younger opponent after the match. After winning two Challenger events in his career, Goffin has certainly come a long way in a short space of time and it was no surprise when his form slumped post Paris.

A broken left wrist put pay to his chances of making progress in 2013, but he bounced back the following summer after a positive performance at Queen's Club before reeling off three straight ATP Challenger Tour titles and then landing his first ATP World Tour title with victory in Kitzbuhel, Austria. After the US Open, where he reached the third round, he captured his second ATP title in Metz. A month later he recorded his first win over a top 10 player by beating Milos Raonic before finishing as runner-up to Federer in Basel. Goffin rose to a career-high No 22 and was named ATP Comeback Player of the Year. After losing out to Stan Wawrinka in the Chennai semi-finals at the start of January the 24-year-old must be regarded as a real dark horse in Melbourne.