San Francisco (USA), Nov 15 (IANS): World champion Magnus Carlsen of Norway edged American star Wesley So as the final stage of the Meltwater Champions Chess Tour got off to a dramatic start here on Tuesday (IST).

Carlsen and So, the two big rivals from the 2021 Tour, went head-to-head on Day 1 of the 2022 Tour Finals in a clash seen by the experts as a potential tournament decider.

Playing in his first Tour event of the year, So battled hard but it was the Norwegian world champion who came out on top, despite a series of blunders.

The opener started with the notoriously drawish Berlin opening but it did reach an interesting game with Carlsen, with the white pieces, having a slight edge before it ended in a draw by repetition.

Wesley So, the newly-crowned Chess.com Global Speed Chess Championship winner, then had Carlsen on the ropes in Game 2, having been allowed to push a pawn to the seventh rank.

But Carlsen dug deep to find defensive resources that stopped So queening. So's winning chances evaporated and the game ended in a draw after 113 moves.

After coming back from the brink, Carlsen hit back hard. With the champion threatening to break through, So played 30... Qa8 which let Carlsen into his position. 35. Qg5+ followed and then the killer 35. Qg5+.

Carlsen had made the breakthrough to go 2-1 up and So was left needing a win in the final rapid game.

It looked like plain sailing for the Norwegian but a sudden one-move blunder in the final game let So level the score. Carlsen miscalculated playing the careless 25... Qg6 that allowed his queen to get pinned after 26. Nf6+ gxf6 27. Rg3. Carlsen was furious with himself. However, So could have played 27.Qxc6 and instead left the door open for Carlsen to set up a fortress.

The world champion, who has previously said he "doesn't believe in fortresses", duly did so and secured the draw he needed to win the match and take his Tour earnings over USD200,000 for the season.

So, playing from Minnetonka, MN, realised his own mistake and said afterwards he "forgot" about Carlsen's defensive possibilities.

Carlsen said: "To be honest, the match today was pretty weak by our standards. We can do better."

In the other matches, Jan-Krzysztof Duda was the first player to win a match -- and USD7,500 -- defeating the Indian teenager Arjun Erigaisi 2.5-0.5. Shakhriyar Mamedyarov came out on top against Rameshbabu Praggnanandhaa in the battle between the youngest and oldest players in the competition.

Shakh, playing from Baku in the middle of the night, took a huge win against the teenage sensation who has set the 2022 season alight. It took a final game grind to beat the 17-year-old 2.5-1.5.

The last match to finish was a tight encounter between Vietnam's speed specialist Liem Quang Le and Dutch No.1 Anish Giri. After four straight draws, the match went to tiebreaks. Giri took the first and then secured the draw he needed in the second to win the match. Giri said after he thought the quality of the games were "very high".

Carlsen plays India's Arjun Erigaisi on Day 2, Liem faces So, Mamedyarov is up against Duda and Praggnanandhaa takes on Giri.