ANDY MURRAY's resurgent recent form makes him one of the favourites to be crowned the ATP World Tour Champion but the Scot will only know he is truly back to the top of his game when he can take down world No.1 Novak Djokovic again.

That is the opinion of Leon Smith, Murray's first coach and current Davis Cup captain, as the days count down to the dazzling showcase finale to the ATP tour at the O2 Arena in London this week. Thrilling back-to-back tournament wins in Vienna and Valencia enabled Murray to qualify for the round robin event with a measure of comfort, where he has landed in Group B and will take on Roger Federer and Milos Raonic after Sunday's opener against US Open runner-up Kei Nishikori.

The real threat to Murray's hopes, however, may be in the other section. Not only is Djokovic a two-time defending champion in this event - he beat Federer in the 2012 final and Rafael Nadal last year - he is on a 27-match unbeaten run indoors and is hardly short of motivation as he seeks to consolidate a year-end No.1 spot. As heartening as Murray's return to fitness and form after back surgery has been, in the calendar year of 2014 he has played Djokovic four times and lost all four, the latest in coming in Paris last week.

"Andy will certainly go in thinking he can win it," said Smith, the Scot who will lead the Great Britain Davis Cup team to a tie with the United States at the Emirates Arena in early March. "He has shown enough in the last five or six weeks to suggest he is getting close to where he has to be. He starts with Nishikori on Sunday and is also in with Federer and Raonic, and these guys are playing great. Just when you say the level can't keep getting better it does.

"Andy is one of the favourites, although Djokovic is obviously the outright favourite and rightly so. That will be the next stage for Andy, getting over the line against Djokovic. But it is something he knows he can do. I think 2015 is going to be great for him. He has got himself really back now, with a lot of hard work. He is fighting so hard on the court."

It is easy to blase about the meeting with Nishikori, against whom Murray has won all three of his previous encounters without dropping a single set. But this is an opponent whose play is almost unrecognisable since hooking up with former grand slam winner Michael Chang.

There has been some badly needed rest for Murray ahead of this week's rigours, but he will have to hit the ground running on the banks of the Thames. "Some rest will help but knowing him he will probably only take one or two days where he will calm it and then he will be right back on it again," said Smith.

"It is too big a tournament for him not really to prepare, not like one of those tournaments where you take a bit of time off then have to play an ATP 250 series event. You are straight in against Nishikori first round, who is playing really good tennis, so he will prepare unbelievably well."