That is the opinion of Arsenal legend Martin Keown.
The Gunners came close to claiming a rare win at Old Trafford on Wednesday night, but twice scuppered their lead against Manchester United.
Emery has battened down the hatches since arriving at the Emirates Stadium, and has spearheaded Arsenal to a 20-match unbeaten run in all competitions.
Such is the competitiveness atop the Premier League table, the Gunners narrowly sit outside the top four on goal difference, however.
Keown, who won three Premier League titles during his 13 years in north London, believes the midweek draw to United showed what Emery’s team must improve on.
“There is still a bit of naivety. I would like to see more nastiness in their back line,” Keown told MailOnline.
“Arsenal went ahead twice at Old Trafford. When that happens, the attitude of the defenders has to be: ‘It’s down to us to keep this lead.’
“When the ball was in and around the box, I saw opportunities for Arsenal defenders to put a foot in but no-one really took charge.
“I look at the three centre halves — Sokratis, Shkodran Mustafi and Rob Holding, who is now injured — and think: ‘Which one is going to develop into the leader?’”
Arsenal conceded their first goal from a free-kick, as a narrowly-offside Ander Herrera was afforded time in the box to cross to Anthony Martial, who buried The Red Devils’ first.
“I know Ander Herrera was offside for Manchester United’s first equaliser but the Arsenal players were looking at one another wondering who was going to clear the ball,” Keown added.
“When I played in the Arsenal back four, the other three were constantly questioning me and I was asking the same of them. We would nit-pick the whole time.”
The second United equaliser was even tougher to digest, as Jesse Lingard latched onto Sead Kolasinac’s lame backpass to score 13 seconds after the restart of Marcos Rojo’s own goal.
Keown believes there’s needs to be greater desire to win in Emery’s backline, if they are to replicate the honours of Wenger’s early sides.
“It was easy for me to come into that back four. The defenders were all snarling and desperate to win,” Keown added.
“These are the qualities that Arsenal’s current defence must develop.”