Thierry Henry believes that Arsenal need to sign four "top-quality" players in order to challenge for the Premier League title, and has criticised Mesut Ozil's performances against the Gunners' rivals.
Arsenal drew 0-0 with league leaders Chelsea at the Emirates on Sunday, leaving Arsene Wenger's team 10 points behind the Blues with five games to play.
Henry won two titles during an eight-year spell with Arsenal, and says Wenger must follow Jose Mourinho's example by seeking key additions to the "spine" of his team this summer.
"Arsenal need to buy four players, they need that spine," Henry told Sky Sports. "They need a goalkeeper, they still need a centre-back, they still need a holding midfielder and, I'm afraid, they need a top, top-quality striker in order to win this league again.
"The best example for me today was Chelsea. They struggled last year and they were still competing to win the league. They now have [Thibaut] Courtois, [Nemanja] Matic, Cesc [Fabregas] and Diego Costa.
"For me that speaks volumes, and we saw it today. A team didn't and a team did, and Chelsea are about to win the league."
David Ospina has displaced Wojciech Szczesny as Arsenal's No.1 this season, but Henry thinks a lack of serious competition for places is costing Wenger's squad.
"He has to [sign players]," he continued. "If you take the goalkeepers, for example, at Bayern Munch, Chelsea, Manchester United and a lot of other teams.
"You need that type of player, you need that competitiveness within the group and you need great players. In order to win the league that has to happen."
Henry scored 174 goals in 254 Premier League games for the Gunners, and says players like Ozil -- who cost Arsenal a club-record £42.5 million -- must step up and make the difference in decisive games such as Sunday's stalemate with Chelsea.
"Players need to perform also," he added. "I will single out Mesut Ozil, who made his eighth appearance against a top-four team today.
"Zero goals, two assists. That is not enough. Since joining Arsenal he has 14 assists. Now if you look at Fabregas at Chelsea, he has 16 assists in one season.
"At one point, I do think, and I do believe, the players have to step up and stand their game up."