Petit, a World Cup and European Championship winner with France, achieved the Premier League and FA Cup double at Arsenal in the 1997-98 campaign.
Arsenal's FA Cup triumph last season was their first trophy for nine years and, ahead of their UEFA Champions League last 16 tie with Monaco, Petit says there are a lack of "killers" within the squad.
"You have to remember the defence that we had," Petit, who also lifted the Ligue 1 title with Monaco, told The Mirror.
"You could rely on [David] Seaman, [Tony] Adams, [Martin] Keown, etc.
"We knew how to travel. When we had to play, we knew how to do that too. I remember one away game at Wimbledon where Tony Adams came to say to me: 'Today, Manu, forget the football. It's war'.
"We knew how to adapt because we only wanted one thing: to win.
"Let's say that the Barcelona of keeping the ball has overtaken that style.
"But today, you have to be more direct and pragmatic. You see that with Germany or Real Madrid.
"Arsenal have very pretty players but there are not 'killers' in this team. At that time, we were tough, we did not play to look good."
