Nadera and Mariano are a half point behind solo leader and top seed Liviu-Dieter Nisipeanu of Romania (Elo 2692), who had a perfect score of four points.
Eleven players were tied at 3.5 points each including 13-year old IM Magnus Carlsen of Norway who beat GM Evgeny Vladimirov of Kazakhstan.
Filipino GM Bong Villamayor (Elo 2390) smashed the Hedgehog defense of GM Ashot Anastasian (2587) in 66 moves of a rook-and-pawn endgame to trail with three points together with 14 others.
Nadera (2390) transposed Izoria’s Queen’s Gambit into the closed variation of the French Defense. Nadera blocked the queenside and opened the Bishop file to counter on the kingside. In an inferior position without space to move his pieces, Izoria (2573) lost on time in 28 moves.
Mariano maintained the initiative of White against the Alekhine defense of Mamadyarov, highly rated at 2657. Mariano (2416) sacrificed a center pawn to centralize his Queen.
and double with the Rook to control the center file. The Filipino IM had mating threats but missed a winning pawn move on the 27th move that would block the pin by his opponent’s Queen. "I would have resigned immediately," Mamedyarov said in post-game analysis watched by supporters from the Filipino community in Dubai. The game simplified with exchanges and a draw was agreed in 31 moves. Mamedyarov is a top qualifier to the World Championship next June in Libya.
A host of 45 grandmasters in a field of 134 players from 39 countries are competing in the sixth edition of the Dubai Open which has grown to become the strongest open chess tournament in Asia. At stake is a total of $40,000 in cash prizes. The tournament is a 9-round Swiss system event.
"Nadera and Mariano may need to score 50 percent in the next five rounds to get a GM norm," predicted World Chess Federation (FIDE) Rating administrator Casto Abundo, the chief arbiter of the Dubai Open. "I have also arranged invitations for Filipinos to this year’s Abu Dhabi Open to give our IMs more chances to get the GM norm," Abundo said.
In round 5, Nelson Mariano plays black against GM Pavel Eljanov (2592) of Ukraine, Barlo Nadera has white against GM Artashes Minasian (2582) of Armenia while Villamayor plays black against GM Mikhail Ulibin (2579) of Russia.