Arsenal would have won the league with three extra key players this season, says Gary Neville.
He says Arsene Wenger's biggest challenge this summer is identifying them.
He said: "Put Costa, Matic and Terry in that team and they win the title.
"So how do they find these? They are not readily available. They need that spine.
"It's whether Arsene Wenger can find those types of players to make the next jump."
Neville's comments are consistent with those of Thierry Henry, who told the channel last week that four new players were needed to challenge for the league.
Arsenal are 10 points behind Chelsea in this season's table, with Jose Mourinho's side clinching the title with a win against Crystal Palace on Sunday.
Arsene Wenger may not feel the same way, especially regarding a striker. He told The Mail that he felt strongly that Olivier Giroud had all the qualities he needed in a centre-forward.
Francis Coquelin's emergence has also answered questions over a defensive midfielder, it's just whether Wenger will release Mathieu Flamini and sign another as a replacement, while the addition of Gabriel Paulista at centre-back in January adds depth to his position.