By Aimee Lewis, CNN

(CNN) -- A quick handshake and it was over. After 20 days and over 50 hours of play, finally there was a result.

Magnus Carlsen did what the greats always do when the tension is at its knuckle-gnawing highest. The Norwegian grandmaster prevailed against his toughest opponent yet, the American Fabiano Caruana, to secure his fourth world chess title.

For most of November there was deadlock. Twelve games, 12 draws, a too-close-to-call psychological battle conducted before a devoted global audience locked at 6-6. And so, in a soundproof studio in a grand Victorian building in central London, the world championship was decided by a series of quickfire tie-breakers for the first time in the competition's official 132-year history.

This was, said World Chess president Ilya Merenzon, the chess equivalent of Muhammad Ali versus Joe Frazer going into the final round, though perish the thought that those two heavyweights had taken 51 hours and 773 moves to settle the "Fight of the Century."

Carlsen, the world No.1, the reigning champion, a 27-year-old who was once described by the Washington Post as the "Mozart of chess," was the favorite to prevail in the best-of-four rapid match.

Not only is the Norwegian regarded as one of the greats in the classical format, he's also the world's top-ranked rapid and top-rated blitz player. This was a man going into the final day with a nine-from-nine record in tie-breakers spanning over a decade, and so it should be of little surprise that Carlsen crushed his opponent 3-0 in the shortened format.

"I feel like I've had a really good day at work today," joked a smiling Carlsen to the delight of a chuckling crowd of fans and reporters.

The buildup to the grand finale had escalated into a crescendo of excitement, so closely contested had the first 12 games been. But when fireworks were anticipated, a wet Wednesday in London served up a damp squib as the tie-breakers proved a challenge too far for the American grandmaster.

"It wasn't a good day for me," he admitted. "I hope I can look back at the match and learn from it."

Caruana -- the challenger, the underdog, the first American to compete for the world title since Bobby Fischer in 1972 -- had not blinked during the three-week stare-off.

But though the difference between Caruana and Carlsen in the classical games was razor-thin -- Carlsen would later say that the American was equally worthy of calling himself the world's best in the longer format of the game -- the New Yorker's rankings in rapid and blitz (No.8 and No.16 respectively) suggested that he would eventually fold in the English capital.

'Stupid opinions'

The Norwegian's hasty offer of a draw in Monday's Game 12 had led to question marks about the defending champion's confidence and courage.

Former world No.1 Garry Kasparov, the only other grandmaster to match Carlsen's global fame, had tweeted that the "shocking draw" had led him to reevaluate. "Tiebreaks require tremendous nerves and he seems to be losing his," wrote Kasparov.

But Carlsen, though not at his best over the last two years, held his nerve and, following his victory, told the assembled media and fans that the likes of Kasparov were "entitled to their stupid opinions."

Not since 1990 had there been a chess match between players this closely ranked. "Fabiano is a really strong player and there's not much to choose between us at this point," Carlsen admitted.

And not since the brilliant Fischer, the first western world champion in the modern era, took on Soviet Boris Spassky at the height of the Cold War in 1972 in a clash of east versus west had there been such international interest.

On the eve of the title decider, tickets were being sold online for £125 (US$160). An hour or so before the 3pm start for the first of the 25-minute tie-breakers, an orderly queue formed outside The College, a spectacular old building in the Holborn district of London.

The predominantly male spectators comprised of the young and old and came from around the world, representing a fraction of the enthusiastic following the live online and TV coverage had attracted this month.

To truly measure the appeal of an event is to scan the number of journalists and photographers in attendance. One room was not enough to home the media sprawl.

The BBC had dispatched a correspondent for a bulletin on that evening's primetime news show, and since the beginning of November a pack of Norwegian journalists had descended on the English capital to cover Carlsen's every move. During the post-match press conference, the World Chess president drew attention to the handful of American reporters in attendance, a rare sight over the last few decades.

The unprecedented spate of draws had left many to question whether the format of the tournament needed to change. Had it been dull, or were these two geniuses playing at an extraordinarily high standard? The president of World Chess, unsurprisingly, pleaded the latter.

"Sometimes you need to give people the opportunity to criticize something otherwise it'll be really boring for them," Merenzon told CNN Sport.

"Overall, we're very happy and we see that chess is becoming a household sport and this is exactly what we want. Even though the result [after 12 games] was a draw, the fight was intense."

No matter the level of understanding of a game which has more possible situations than there are atoms in the universe, few spectacles are more compelling than watching two humans in a unidirectional glass booth vying for a crown which has been owned by only a handful of men. Carlsen is just the 16th world champion.

Sitting at either side of a square table, barely a meter apart, these grandmasters with superhuman powers of concentration played as if unaware that on the other side of the glass would be an audience of hundreds seated in a darkened room; peering, filming, picture-taking (though phones were officially not allowed); behaving as if the boxed finalists were a rare caged species to be gawped at.

It was Dutch grandmaster Hans Ree who once said that chess was a game beautiful enough to waste your life for. It is certainly a game for those who believe Test cricket or baseball to be hurried and short-lived.

World Chess will now attempt to build on the popularity of these twentysomething grandmasters, whose rivalry has helped elevate this event to a wider audience. As Caruana's agent, Eric Kuhn, told CNN Sport at the start of the tournament, the players "represent everything that is now."

With the game particularly popular with teenagers in Asia, World Chess is already in talks with Chinese companies in a bid to expand further in the world's most populous country. For this edition of the championship, a Tinder-style app was developed to unite like-minded chess enthusiasts and World Chess has plans to introduce more gaming apps over the next few weeks.

"We know for a fact that while the championship is happening it's going to be crazy, the only upsetting part is it's really hard to convince people before," added Merenzon.

"We have so much planned for the digital space and we'll be rolling it out in the next weeks. We have this amazing logo and graphics from the championship -- on the table it says 'The World is Watching' so we'll probably produce merchandise with that specific logo."

Had the nerdy but stylish Caruana, described as "a computer" by Carlsen, won the title, Merenzon admitted that the future of chess would have been "completely different" because of the impact the 26-year-old Italian-American's title win would have had in the US.

But the pressure of attempting to emulate Fischer did not weigh heavily, insisted Caruana. "I felt a lot of pressure, but I don't think I had added pressure because I was the first American challenger in a long time," he said.

Instead, it is the intuitive and charming Carlsen -- a grandmaster since 13, a world champion since 2013, a model for fashion label G-Star, a multi-millionaire -- who remains the game's superstar. His greatness is assured.

"I will celebrate for the next two years," said the Norwegian when asked how he planned to toast his victory.

But though there can only be one champion, both have galvanized the game. Chess has crossed into the mainstream.