Alexis, against West Brom, is set to make his first Premier League start tonight since a £60million deadline-day move to Manchester City collapsed after the Gunners failed to sign Monaco's Thomas Lemar as a replacement.
“Alexis is an important player for us," said Koscielny. “I know it was a difficult situation with the transfer window but now it's finished and I think he is focused on his job, on his performance and on his club.
“He's an Arsenal player and he knows that he needs to play and he needs to score some goals and give assists to be better. He's still working every day like he did before, so the most important thing is to keep his head cool and just play and enjoy."