New Delhi:Top seed Alexei Dreev of Russia asserted his class by thumping back into joint lead after a superb win against overnight sole leader GM Dibyendu Barua in the sixth round of the Parsvnath International Open Chess championships in New Delhi on Thursday. Barua's defensive approach resulted in a lop-sided affair lasting 40 moves on the top board at the Indira Gandhi Indoor Stadium. On the fourth board, GM Safin Sukhrat of Uzbekistan defeated higher-rated Abhijit Kunte to join Dreev in the lead, which was also shared by S Arun Prasad after his impressive victory against GM Saidali Iuldachev of Uzbekistan. Prasad also strengthened his chances of earning second GM norm. The leaders at 5.5 points apiece, were followed by 19 players on 5 points including Barua, Yuri Drozdovskij of Ukraine, Ahmed Adly of Egypt and Ziaur Rahman of Bangladesh. On the top board, Barua, playing white, employed Classical Sicilian and became a pawn down in the middle game to give the Russian a huge positional advantage before uncorking a rook sacrifice, which exposed his castled position to seal the matter. "I played very passive and was not really very confident against Dreev," said Barua after the game. Prasad played Sicilian Najdorf with the black but was surprised when Iuldachev sacrificed his queen for some positional compensation. But the former Asian junior champion hung on to slowly convert his material advantage in to a full point. Kunte, who had a better position as white, tried too hard to break the defenses of Shukhrat, who countered him well to romp home.