ANDY Murray begins his reign as world number one against Marin Cilic on Monday at the ATP World Tour Finals after an incredible 2016.

Here, we look at Murray's campaign and his journey to the top of the rankings.

AUSTRALIAN OPEN, January

Murray made it to the final of the Australian Open before losing to Novak Djokovic - the man he has replaced as number one. The Scot defeated David Ferrer in a quarter-final clash which lasted over three hours before coming out on top in a gruelling five-hour semi-final against Milos Raonic. Murray faced Djokovic in the final - their fourth Melbourne encounter, with the Serb having won the previous three. Djokovic proved too strong once again, brushing Murray aside in straight sets.

MADRID OPEN, May

The 29-year-old suffered another final defeat to Djokovic as the Serb won 6-2 3-6 6-3 in the Spanish capital. The loss saw Murray drop to world number three, with Roger Federer moving above him. Shortly after the tournament it was announced that Murray and Amelie Mauresmo had mutually agreed to end their coaching partnership.

ITALIAN OPEN, May

Murray responded positively to the Madrid setback, winning every match in straight sets, including a 6-3 6-3 triumph over Djokovic in the final. He regained the world number two position as a result.

FRENCH OPEN, June

Murray struggled past Radek Stepanek in the first round and endured another five-setter against wildcard Mathias Bourgue in his next match. He found his rhythm and eased past Ivo Karlovic, John Isner and Richard Gasquet before beating defending champion Stan Wawrinka to reach his first ever final at Roland Garros. Again Djokovic stood between him and a Grand Slam title and the Serb won it in four sets after Murray had taken the first.

WIMBLEDON, July

Murray cruised to his second Wimbledon title, conceding just two sets throughout the tournament - both of those coming in a hard-fought quarter-final against Jo-Wilfried Tsonga. It was the first time the Scot had not come up against Djokovic or Federer in a Grand Slam final as he faced Raonic, beating the Canadian in straight sets.

RIO OLYMPICS, August

Murray successfully defended his Olympic crown from London 2012 as he edged past Argentina's Juan Martin del Potro 7-5 4-6 6-2 7-5 in four gruelling sets in over four hours.

CHINA OPEN & SHANGHAI MASTERS, October

The route to number one began to open up as Murray won two tournaments in China without dropping a set.

VIENNA OPEN, October

A seventh tournament victory of the season took Murray's prize money past $10million.

PARIS MASTERS, November

Djokovic's quarter-final defeat to Cilic meant Murray would become the new world number one if he could reach the final. The Scot came through an intense quarter-final against Tomas Berdych and secured number one spot when Raonic pulled out of their semi-final due to a leg injury. Murray went on to win the competition, defeating American Isner in the final.