Indian maestro Viswanathan Anand's campaign at the Norway Chess tournament suffered a setback after losing to Azerbaijan's Shakhriyar Mamedyarov. Anand lost to Mamedyarov in the ninth round.
On the other hand, Anand's arch-rival Magnus Carlsen shot into sole lead with a win over Frenchman Maxime Vachier-Lagrave.
Anand showed impressive form with a victory over Norwegian star Carlsen to lead the standings after the fifth round but was outgunned by Mamedyarov in 22 moves in the Classical match in a Petroff Millenium Attack game late on Thursday.
As the tournament resumed after Wednesday's rest day, the 37-year old Azerbaijan player capitalised on an error from the Indian veteran to pick up three full points.
Anand, who was in second spot behind world No.1 Carlsen after seven rounds, slipped to third with 13 points at the conclusion of the eighth and penultimate round.
Carlsen is the sole leader with 15 points followed by Mamedyarov on 14.5. Vachier-Lagrave trails Anand by half a point in fourth spot.
In the other matches of the day, American Wesley So, who won the Blitz event that preceded the Classical tournament, lost in the Armageddon to the experienced Bulgarian Veselin Topalov and Teimour Radjabov tamed Hao Wang (China) in the sudden death tiebreak.
Dutch player Anish Giri, who has had a stuttering campaign, outlasted Norway's Aryan Tari in 61 moves in the classical match to score three points.
The ninth and final round will be played later on Friday night.
In the Norway Chess tournament, the players take part in a Armageddon (sudden death) in case of a draw in the classical match.
(Inputs from PTI)