Chelsea great Gianfranco Zola believes the Premier League champions made the right decision selling Diego Costa as they benefit from the arrival of Alvaro Morata.
A deal reportedly worth €60 million will see Spain international striker Costa return to La Liga side Atletico Madrid in January, having fallen out with Chelsea boss Antonio Conte.
Costa helped Chelsea to two Premier League titles and EFL Cup silverware but Zola feels the 28-year-old's departure makes sense for the club especially after signing former Real Madrid forward Morata, who scored in Wednesday's 2-1 Champions League victory at Atletico.
"I have no doubt that it was right for him to go. He probably has a problem, the team is not made by one player, and I think it's better for him to go," Zola told Sky Sports.
"On the temporal level Morata is not on the same level as Costa. Technically he is a great player, he obviously has a lot of qualities, good in the air, good feet.
"He has been with Juventus, Real Madrid, big teams, but didn't play regularly, and I want to find out why. And this year I think I'm going to get the answers."
Morata has hit the ground running since joining from Spanish and European champions Madrid, scoring seven goals in all competitions.
Former Manchester City and Liverpool attacker Craig Bellamy added: "Costa is a brilliant player, Chelsea fans love him, he is always a threat, always involved, but clearly something happened. And that's between the manager and himself. It helps that if Costa does leave you can bring in Morata.
"At Real and Juventus there is always going to be competition for places. But you look at Chelsea at this moment, he does look like the main man. I think he could add something different to Chelsea, especially away from home.
"I love the way he is always on the shoulder. He can do that a little bit more, and a little bit better than what Costa did."