Mikel Arteta is keen to raise the level of competition within his Arsenal squad this summer. In terms of his defensive contingent, he has already done that with the signing of Riccardo Calafiori. The Italian’s arrival at Arsenal will see him compete for game time at left-back as well as in the heart of the defence. This means that the likes of Oleksandr Zinchenko, Jurrien Timber, Takehiro Tomiyasu, Jakub Kiwior, and Gabriel Magalheas will all have to be on top form in order to feature regularly in Mikel Arteta’s starting XIs. Zinchenko has embraced this extra competition, and Arteta will want …