Arsenal will continue to struggle defensively as long as they have David Luiz and Sokratis Papastathopoulos in the starting XI, Roy Keane says, because the pair are ‘not good’ centre-backs.The duo have been the preferred pairing for Unai Emery this season, but the Gunners have not kept a clean sheet in any of the five Premier League matches they have completed so far.Arsenal had conceded 10 times while both the Brazil and Greece internationals have been on prior to Tuesday, with their only clean sheet came in the opening game of the campaign – when Calum Chambers partnered Sokratis in the middle of the back line. Article continues below Editors’ Picks Ox-rated! Dream night in Genk for Liverpool ace after injury nightmare Messi a man for all Champions League seasons – but will this really be Barcelona’s? Are Chelsea this season’s Ajax? Super-subs Batshuayi & Pulisic show Blues can dare to dream Time for another transfer? Giroud’s Chelsea spell set to end like his Arsenal career Nevertheless, Emery opted to stick with the pair on Monday as they lined up against Manchester United at Old Trafford. Although the north London side headed into the game on a three-game winning streak, Keane feels the team look weak when Luiz and Sokratis are on, arguing that they do not enjoy defending.”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.” Check out Goal’s Premier League 2019-20 fantasy football podcast for game tips, debate and rivalries.