GM (2005)

He took his first placements in 2002, ranking at #2 and #5 respectively in the “under 16” category of the Ukrainian and European championships. Subsequently, he has placed highly in championship tournaments around the world, including taking first place in the Summer Olomouc Open in the Czech Republic (2005), the Breizh Masters of France (2006 and 2007) and the Instalplast in Ukraine (2006).

In 2014 Oleksiyenko tied for first with Baadur Jobava and Sergey Fedorchuk, placing third on tiebreak, in the David Bronstein Memorial in Minsk.

In 2015, he won the Karen Asrian Memorial in Jermuk with a score of 7/9, edging out Anton Korobovand Samvel Ter-Sahakyan on tiebreaks