The ATP World Tour Finals will be hosted in London until 2020, ATP executive chairman and president Chris Kermode has announced.
The week-long season finale for men's tennis has been staged at the O2 Arena in Greenwich since 2009 and the partnership was due to expire in 2018.
However, despite interest from a number of high-profile cities, the ATP has now committed to London for an additional two years.
The event will also take on a new four-year title sponsorship with Japanese innovation company the Nitto Denko Corporation, and be known as the Nitto ATP Finals.
At an announcement at the Shard in London on Thursday, Kermode said: "We're pleased to announce we are going to stay here in London through to 2020.
"We had huge amounts of interest globally. We looked at various regions around the world, weighed up the pros and cons, and decided to stay in London."
The ATP Finals brings together the eight top-ranked men's singles players and doubles teams, and since 2009 has attracted more than 250,000 fans on site every year.
Britain's Andy Murray beat Novak Djokovic last November to clinch the title for the first time after Djokovic had previously won the tournament every year since 2012.
Victory also meant Murray finished 2016 ahead of Djokovic as world number one.
Boris Becker, who won the ATP Finals three times and was Djokovic's coach until December, said: "As a coach last year to watch one against two playing for the final spot - it doesn't get any bigger than that.
"It's a showcase for sport and entertainment. The way every round-robin match could be a final of a masters series or grand slam so there are no first round slow matches. The quality of matches is unbelievable."
The ATP Finals has previously been held in locations like Shanghai, Houston and New York among others and Djokovic has before led calls for the host city to be rotated.
Kermode said: "There is a school of thought to move it around to expose tennis in different regions.
"But time has changed, where the exposure of the sport through TV in particular makes that less important. People have access to it and can see the event live.
"I believe all the best sporting events in the world are in the same parts of the calendar, at the same venue - you know where (Royal) Ascot is, Wimbledon is, the US Open is, the Monaco Grand Prix - they are set and always in the same venue."
The ATP Finals first ran in Tokyo in 1970. This year's tournament will be held from November 12 to 19.