Petr Cech gifted Chalov the opener when he failed to parry clear, and the Arsenal man between the sticks put one on a plate for Nababkin for the second.
In an almost carbon copy of the first, a long range effort was flapped at by Cech only for Nababkin to follow it up and score.
Arsenal, who cruised into the game with a three goal advantage, were suddenly not as comfortable in the tie.
12 April 2018