Arsenal boss Mikel Arteta stands by playing Granit Xhaka at left-back.
In Kieran Tierney's absence Arteta has gone with Xhaka ahead of natural fullback Nuno Tavares.
He said, "When I put a player on the pitch I see he's in the right position to do that.
"Look at the stats when Granit plays at left back. You don't get much better than that.
"When I'm convinced to do something that I believe is best for the team I do it."
Meanwhile, after r another injury assessment, a return for Thomas Partey before the end of the season is "not looking very positive," says the Arsenal boss.
Arteta refused to comment on why Alexandre Lacazette was absent from training on Friday but says there is a "good possibility" the France forward is available for Saturday's match against Southampton.