ATP reaps rewards of record crowds as Andy Murray, Roger Federer and Co prove star attraction at O2 Arena No fewer than 263,229 people came through the doors, out of a theoretical maximum of 267,000, which will strengthen the event's hand as it continues to fight for its place on the tennis calendar. The O2 Arena recently won a two-year extension to its deal, so the World Tour Finals will be staged in London until at least 2015. But this event has traditionally been nomadic - London will represent its longest stay in one place since the 1980s - and the assumption is that it will be on the move again in 2016. There was no formal bid process when London won its two-year extension, but the Association of Tennis Professionals had plenty of interest from rival suitors: New York, Moscow, the moneymen of the Middle East. But the city to watch might be Rio de Janeiro, which was recently awarded an ATP 500 event - the second tier of the tour, or the third if you count grand slams - starting from 2014. For a city desperate to extend its sporting legacy after the 2016 Olympics, the timing would seem perfect if Rio could bring in the world's best tennis players for an end-of-year showdown. There is also a push from the ATP to tap into the potential of South America, just as there was a push to move into Asia in the mid-2000s, as reflected in the five seasons the World Tour Finals spent in Shanghai. The counter-argument is that the London event has been staggeringly successful and lucrative. The O2 Arena is the most profitable single-event arena in the world, and this is its biggest earning week of the year, because there are two sittings on seven of the tournament's eight days. It is like having 15 Beyoncé concerts in a week. The income the World Tour Finals generates makes a significant contribution to the ATP's overall revenues, which reached a record level of almost $600 million (£378m) this year on the back of the fascinating narrative of men's tennis. You can be sure, though, that there will be some hefty bids coming in from alternative hosts as the O2"s latest contract begins to wind down. Deliberations are expected to start during this tournament next year, although they could take 12 months to play out.