Grandmaster B Adhiban suffered a defeat at the hands of second seed Hikaru Nakamura while the P Harikrishna also suffered a setback by playing a draw with Aleksandr Lenderman in the fifth round of the Masters section of Tradewise Gibraltar chess tournament here.
Aided by his brilliant victory, Nakamura stormed into sole lead with his fifth win on the trot and the American is now followed by five players including top seed Veselin Topalov of Bulgaria -- a half point behind.
Harikrishna slipped to the joint sixth spot after his second straight draw and the highest rated Indian here shares this spot with 16-others.
Grandmaster Surya Shekhar Ganguly, Sandipan Chanda, V Vishnu Prasanna and Adhiban are also on four points at the half way stage in this 175000 Pounds Sterling tournament.
The day's best result from the Indian perspective was recorded by Grandmaster M R Venkatesh who got the better of higher-ranked English Grandmaster Gawain Jones in the upset of the day. Venkatesh moved to 3.5 points almost putting an end to the hopes of Jones in this event.
Apart from Venkatesh, V Vishnu Prasanna continued with his impressive form at the expense of Sebastian Bogner of Switzerland while Neelotpal Das outwitted Mateusz Bartel of Poland to also move to 3.5 points.
Adhiban was caught off-guard in the opening. Nakamura with his black pieces sprang an early surprise by going for the Queen's gambit accepted on his second turn. Known for his bold and positive play, Adhiban went for a principled variation but the American had prepared a shocker.
Adhiban won a rook for a minor piece early in the opening but Nakamura got good piece-play as compensation. As the game progressed, Adhiban missed a tactical trick and ended up losing a minor piece after which the resulting technicalities were child's play for Nakamura. The game lasted 55 moves.
