SAME old Andy, always winning. Andy Murray says he doesn't feel any different since acquiring the title of the world's best tennis player on Monday and there must have been little discernible difference also yesterday for his vanquished opponent. The 29-year-old from Dunblane wisely opted out of watching Scotland's World Cup qualifier at Wembley last week but, playing as World No 1 for the first time, he had no problems producing a world class 90 minutes in London to get the right result against the dangerous Marin Cilic.

The Croat's victory against Novak Djokovic in Paris last week had led indirectly to this native of Dunblane ascending to the summit of the sport but the 2014 US Open winner was unable to summon up a similar performance to stop the new number one racking up his 20th successive tour win. While the perfectionist in Murray left the o2 arena ever so slightly irked by four double faults in the first set and the indignity of having to face 10 break points, by the end a comfortable 6-3, 6-2 scoreline gave him the perfect start he craved to his ATP World Tour Finals campaign. The 29-year-old is now just two matches short of his best-ever winning run of 22, also achieved this year, and ironically brought to an end by Cilic in the Cincinnati Masters in August.

"It was a great reception obviously," said Murray. "A really, really good atmosphere. It was obviously nice to play in that stadium with the crowd like that. It obviously helps.

"I didn't feel any more nervous than usual," he added. "It's just quite different conditions in there than what we've been practicing in during the week. Obviously playing with a packed crowd, it changes things a bit. Maybe some of the errors at the beginning were more getting used to playing in new surroundings again."

Nowhere else does it quite like the o2 when it comes to showcasing the superstars of world tennis. With overblown introductions borrowed directly from the X Factor, a court bathed in blue light and a bass-heavy soundtrack which grabs you in the pit of the stomach, the Scot was given the full works as he strode on court as the best player in the world for the first time. London has this tournament until 2018, but it is almost certainly here to stay. It is doubtful any other city in the world could shift as many tickets for two sessions a day.

He may be feeling on top of the world right now but the World Tour Finals is one event which Murray still has to tick off his bucket list. This is his eighth appearance in the season-ending event, having never got beyond the semi-finals. Unless, that is, you count his ad hoc appearance on finals day in 2014, where he stood in at short notice for the injured Roger Federer. What better time than this year - basing himself at his Surrey home for the first time - to end that unfortunate run than this year, when he knows victory would be sure to keep him as the top dog of world tennis when 2017 begins.

Cilic was clad in garish white, yellow and black Bermuda shorts but he had not come here as a tourist. Hoping to benefit from some inside info as he works with Murray's former coach Jonas Bjorkman, this was the Croat's second invite to this event and he found himself where Murray was last year, in the sense that he was also casting one eye on an imminent Davis Cup final, against Argentina in Zagreb. The Scot reminded him afterwards of another proud statistic. "I've never lost to one of my ex-coaches, so I don't know," said Murray. "It obviously hasn't had, you know, a negative effect on me."

A strange first set was strewn with errors from both men, with break points arriving in each of the first five games. Murray served four double faults and faced four break points, even if he generally produced his more assured tennis at moments of stress, particularly when he drove Cilic to distraction with the kind of line and length usually reserved for a Test cricket bowler as he broke back for 3-1. Both of his break point chances on the Cilic serve were taken as he took the set 6-3.

Yet while his competitor for the No 1 spot, Novak Djokovic, had appeared agitated on Sunday, Murray - a few odd gestures aside - generally played with the calm assurance of a man who cannot stop winning tennis matches. Watched by speaker Jon Bercow, Olympic diving star Tom Daley and Chelsea winger Pedro, an attritional second set finally began to turn his way as a couple of big forehands did the damage as he broke for 3-2 and then 5-2. Sensing the chance to end matters there and then, that is precisely what he did, the five games he lost comfortably moving him to the top of Group John McEnroe.

In the six days he had spent with Ivan Lendl in London, the words 'World No 1' hadn't come up at all. "I spoke to him about it on the Saturday night in Paris," said Murray, who will now face Kei Nishikori tomorrow afternoon. "But since we've been here, I haven't spoken with the team about it, not once. The last few days, I haven't thought about it too much."