JUSTIN ROSE (ENG), 34
World ranking: 7
The South Africa-born Englishman enjoyed his greatest success at the Open back in 1998, when he finished in a tie for fourth place as an amateur. Early struggles in his career were soon forgotten as he rose to No. 3 in the world in 2013, winning his first Major the same year at the US Open. A gifted links player and winner of last year's Scottish Open, Rose will be looking to produce his best golf on a course where he won the 1997 St Andrews Links Trophy, also as an amateur.
LOUIS OOSTHUIZEN (RSA), 32
World ranking: 17
The South African stunned the world of golf in 2010 when he won the British Open at St Andrews with a brilliant performance against the odds. A former world No. 4, he has seven wins on the European Tour and came close to winning the US Open last month at Chambers Bay, where he finished tied for second with Dustin Johnson and just one shot behind Spieth.
DUSTIN JOHNSON (USA), 31
World ranking: 4
He has not played since missing that 12-foot putt to win the US Open but has shown his ability to bounce back from tough finishes. He won the BMW Championship a month after falling short at the 2010 PGA Championship, and won the Barclays weeks after finishing second at the 2011 British Open at Royal St George's. When the Open was last at St Andrews, he finished in the top 15. If he putts well this week, he has a great chance of finally winning his first Major.
PHIL MICKELSON (USA), 45
World ranking: 21
One of the most popular players to ever play the sport, the five-time Major winner is a contender to win at every tournament he enters. The burly 45-year-old from San Diego won his first Open in 2013 when he became the first player to win the Scottish and British Opens in consecutive weeks. He began the final day five strokes off the lead but produced a magical 66 to win by three shots from Sweden's Henrik Stenson then.
RICKIE FOWLER (USA), 26
World ranking: 5
The Californian is still looking for his first Major success after a series of near misses and finishing runner-up last year at the British and US Opens, third at the PGA Championship and fifth at the Masters. Arrives at St Andrews in a rich vein of form, having come from behind to win last weekend's Scottish Open at Gullane. Also won his second PGA Tour event in May when he defeated Sergio Garcia and Kevin Kisner in a play-off at the Players Championship. He is firmly established in the world's top 10 and only needs a Major breakthrough to further enhance his reputation as one of the stars of the game.
JASON DAY (AUS), 27
World ranking: 8
He has finished runner-up at Major tournaments on three occasions, the 2011 and 2013 US Opens as well as the 2011 Masters. But his results on European soil have yet to produce a win and his best result at the British Open was a tie for 30th in 2011. The Queenslander reached a career-high ranking of world No. 4 last year thanks to victory in the WGC-Accenture Match Play Championship.