It was certainly a tale of two goalkeepers as Arsenal and Shakhtar Donetsk went head-to-head in the third matchday of the new Champions League season. The only goal of the game, despite the best efforts of Gabriel Martinelli, would go down as a black mark against Dmytro Riznyk’s name. As Martinelli cut inside and fizzed a shot at goal with his trusty right boot, the ball rebounded off the base off the post, onto Riznyk and into the back of the Shakhtar Donetsk net. A moment of cruel misfortune for a man who, by and large, was the Ukrainian giants’ finest performer on the night. Riznyk denied A…