THIBAUT COURTOIS admits struggling Chelsea are missing Manchester United midfielder Nemanja Matic.
Former United defender Phil Neville accused the Blues of making one of the poorest decisions ever seen in the Premier League on Tuesday by selling Matic to the Old Trafford giants last summer.
And ahead of Sunday's reunion with the £40million man, who returns to Stamford Bridge with his new side four points ahead of the champions in the table, Courtois admits they could do with him back.
The Chelsea goalkeeper said: "We know Nemanja's qualities, he is someone who last year gave us the balance as well.
"Our midfield is very good, we have very strong players. But if you have two injuries in midfield then of course you can say we miss Nemanja because he is another quality player and he is doing well in Manchester."
Matic has been hailed as the signing of the summer in some quarters for the way he has bossed the United midfield.
And Chelsea could have done with him against Roma, who blew them away 3-0 in a Champions League romp in the absence of injured midfielder N'Golo Kante.
The Frenchman remains a doubt for Sunday's game with a hamstring problem, while Danny Drinkwater is not yet fully fit either.
Some Chelsea fans were surprised Matic was allowed to join a title rival and Neville slammed that decision as a shocker during his commentary on the Roma game for BBC Radio 5 Live here in Rome, where Chelsea conceded their 11th goal in six games.
He said: "What has gone wrong for Chelsea? One word. Matic. It's as simple as that. The minute they sold Nemanja Matic was a mistake.
"When you had Matic sat in front of you, alongside Kante, there was protection. Whoever made that decision needs sacking. That is one of the poorest decisions I have ever seen in the Premier League.
"You replace him with someone who is going to do the same job. Tiemoue Bakayoko is not that player. He is not a holding midfield player.
"They didn't replace Matic. I wouldn't have let him out of the building, I would have chained him to the training ground walls."
Even the player himself confesses he still cannot explain why the champions allowed him to leave.
"I cannot say," said Matic. "The only thing I can say is that I'm happy to be part of this club. I'm happy to working with Mourinho. That's all I can say."
As for going back to Stamford Bridge, Matic added: "I don't know what the reaction will be like. When I played there I always gave me 100 per cent and we won two titles together and won a cup. I'm sure they respect that but if not I don't really care.
"As I said, when I played at Chelsea I give always my best to help the team but now Manchester United is my club and I will try to win there.
"I feel when I played there, I showed them my quality. We won the title twice and also two cups, so I don't have to prove to them anything. I just have to prove something to my new club.
"Of course, I spent a good time there, three-and-a-half years, which is a long time, and of course it's going to be something special again for me to play again in that stadium. But now I'm on the opposite side, I have to be professional and do the best for my team."
Matic has certainly shone since his reunion with Mourinho, turning in a long string of consistent displays and showing why the United manager insisted only last week that the Serb, 29, and not Tottenham's Eric Dier, was always his first choice target for a holding central midfield position.