Andy Murray has set his sights on retaining his world number one ranking for a long time following his maiden success at ATP World Tour Finals in London on 20 November.

The Scot defeated Novak Djokovic in straight sets as the final scoreline was 6-3, 6-4 in Murray's favour. He replaced the Serbian tennis star to become the new world number one after making it to the final of the Paris Masters, which he went on to win.

Murray has been in fine form in the second half of this calendar year and finished the season on a high by registering a victory over the defending champion at The O2 Arena on Sunday. The 29-year-old is aware that it will be a difficult task for him to retain his position at the top and the 2016 Olympic gold medallist wants to add top honours to his name over the next few years.

"I would like to try and stay there, obviously. It's taken a huge effort the last five, six months to get there," Murray was quoted as saying by ATP's official website.

"I would obviously like to stay there. I'm aware that's going to be extremely difficult because I had a great year this year. I only managed to do it by one match. To repeat that again next year is going to be extremely difficult."

"I want to try and achieve as much as I can these next few years because I'm not going to be around forever. I'm not going to be able to play at this level and play this many matches into my mid-30s. The young guys are going to keep improving and getting better."

Murray was delighted to register a victory over Djokovic at the ATP World Tour Finals, who according to the British tennis star, has been his main rival in this calendar year.

"He's been my main rival really throughout my career. We've played in all of the slam finals, Olympics, obviously here now, and a match to finish the year No. 1," he added.

"We played in loads of Masters 1000 Series finals, as well, and are one week apart in age. It obviously a very important win for me. It was just a huge match to finish the year, to try and finish No. 1. This is a major event, as well, and one I've not done well in in the past. So it's been a great week," he said.