Wesley So suffered his first defeat of the tournament at the expense of Shakhriyar Mamedyarov of Azerbaijan in their Armageddon play to slip to share of third with his conqueror after five rounds of the Norway Chess tournament in Stavanger Monday.
Needing just a draw to seal the win, So failed to convert his moves as Mamedyarov prevailed after 39 moves of an English duel.
The result allowed Mamedyarov, who drew their standard game in 47 moves of a Queen’s Gambit Declined earlier, to catch up on So at No. 3 with 8.5 points apiece.
Despite the defeat, So remained in title contention as he was just 1.5 points off the pace.
Former five-time world titlist Vishwanathan Anand of India stunned the younger current world champion Magnus Carlsen also in Armageddon to reclaim the solo lead with 10 points, or half a point above the Norwegian star.
So could inch closer and even surpass Carlsen and Anand if he could come through with better result against his last four foes—Maxime Vachier-Lagrave of France, Aryan Tari of Norway, Wang Hao of China and ex-world champion Veselin Topalov of Bulgaria.
The nine-round tournament uses a novel scoring format where a win in standard is worth three points and a triumph and a loss in Armageddon is worth 1.5 points and one point, respectively.