In the fifth round of the competition, Tabatabaei, with a rating of 2692, drew with his American opponent Hans Niemann with a rating of 2667.
The Iranian chess player has lost about five live ratings by gaining two wins, 2 losses, and a draw in the sporting event.
The event features nine super grandmasters, including the rising star of Indian chess, Dommaraju Gukesh, and the American sensation Hans Niemann.
The 13th edition of the London Chess Classic is taking place on December 1-10 as a 10-player single round-robin with a classical time control.
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