Roy Keane believes Arsenal duo David Luiz and Sokratis don't enjoy defending.

After starting in Monday's 1-1 draw with Manchester United, the duo only have one clean sheet whilst playing together this season.

"No matter how good a coach you are, if you've got players who can't defend, you're going to give up shots, you're going to give up goals," ex-United midfielder Keane said on Sky Sports.

"And I still think the spine of Arsenal is very weak, so no matter how good a coach you are, those weaknesses are there.

"I think the way to fix it sometimes is through experienced players, but these things aren't going to change. Maybe his hands have been tied a little bit with the transfer market, I know he's spent money on attacking players.

"But we keep going back to it, you've got to have a decent back four, a decent foundation, and I don't think they have that.

"No matter how brilliant he is, you look at their two centre halves, I don't care who's coaching them, they're not going to improve defensively because I don't think they're good defenders.

"I don't think they smell danger, I don't think they enjoy defending. And that's up to the manager himself, get better defenders."