Indian Grandmaster Viswanathan Anand suffered his fifth straight defeat in the $150,000 Legends of Chess online tourney, going down 2-3 to Peter Leko of Hungary.
The former world champion got off to a good start and won the first game of the best-of-four contest. The next two games were drawn before Leko levelled by winning the fourth.
The Hungarian then claimed the Armageddon (a tie-breaker) to ensure Anand remain winless and at the bottom of the points table.
Anand, who is making his maiden appearance on the Magnus Carlsen Chess Tour, had earlier lost to Peter Svidler, Magnus Carlsen, Vladimir Kramnik and Anish Giri.
World No1 Carlsen bounced back strongly to avoid an upset, beating veteran Vasyl Ivanchuk 3-2 to stay on top.