Norwegian chess superstar Magnus Carlsen on Wednesday cemented his reputation as the game's greatest player after demolishing US hopeful Fabiano Caruana in a winner-take-all world championship final.

The 27-year-old won three successive rapid-chess tiebreakers in a display of intuition and guile that overwhelmed the 26-year-old American in London.

Carlsen was gracious after his thumping win put an exclamation point on a defensively-minded series that went to tiebreakers after 12 regular game draws.

“Caruana is clearly the toughest opponent I have faced,” Carlsen told Norway's NRK television . “It was hard.”

Caruana's loss will crush American fans who had hoped to see the coveted crown come home for the first time since Bobby Fischer defeated the Soviet Union's Boris Spassky in a 1972 Cold War-era thriller.

“I had a bad day,” a dejected Caruana told NRK . “I didn't even put up a fight.”

- Vindication -

The fearless performance will go a long way to cementing Carlson's claim to being the best the “King's Game” has ever seen -- a title some still bestow on Soviet-Russian legend Garry Kasparov.

Kasparov himself appeared in awe of Carlsen's performance in a rapid-chess format that has seen many grandmasters before him wilt under the mental strain.

“Carlsen's consistent level of play in rapid chess is phenomenal,” Kasparov tweeted.

“We all play worse as we play faster and faster, but his ratio may be the smallest ever, perhaps only a 15 percent drop off. Huge advantage in this format.”

The games marked a complete departure from the string of regular-series draws that saw both players too fearful of the others' prowess to mount any risky attacks.

Those tense tugs of war were a testament to the prodigious talent of the up-and-coming American Italian. Caruana entered the series as the game's second-ranked player and just three points in the rankings behind Carlsen's massive 2,835.

Chess experts said Carlsen appeared to be rattled by the Miami-born yoga lover in a memorable game 10.

Carlsen was only too happy to agree to draws in the final two matches -- the last one from a winning position that saw Kasparov shake his head in disbelief.

“In light of this shocking draw offer from Magnus in a superior position with more time, I reconsider my evaluation of him being the favourite in rapids,” Kasparov tweeted after Monday's match.

“Tiebreaks require tremendous nerves and he seems to be losing his.”

Another Russian chess master, Vladimir Kramnik, added: “He might be tired of tension, fighting; maybe even of chess itself to a certain degree.”

- 'Stupid opinions' -

But the Norwegian seemed set on deciding things in Wednesday's speedier round -- a format that saw him beat Sergey Karjakin in the 2016 title match in New York.

“It feels good after all the criticism that I got Monday,” Carlsen admitted after his victory.

“I think I made the right decision ... As for the opinions of Garry and Vlad, I mean, they are entitled to their stupid opinions.”

The man once dubbed the “Mozart of chess” by The Washington Post will not have to defend his title again until 2020.

His first came when he toppled Viswanathan Anand on the former champion's home turf in India in 2012. Carlsen defended his crown in a rematch played the subsequent year in Russia.

But he really began making a name for himself when he managed to draw Kasparov -- then regarded as the best of all time -- at the tender age of 13.Carlsen actually beat Kasparov's compatriot and nemesis Anatoly Karpov at the same event.

But the Norwegian seemed nostalgic for a more recent time just a few days ago in which he played every game without fear. “My favourite player from the past is probably myself like three-four years ago,” he said.