Former Arsenal midfielder Paul Merson has claimed that Chelsea may live to regret selling Nemanja Matic, Ruben Loftus-Cheek and Nathaniel Chalobah during the summer transfer window.

Blues boss Antonio Conte is understood to have been left largely frustrated by the lack of incoming arrivals at Stamford Bridge, despite landing Davide Zappacosta and Danny Drinkwater on deadline day.

Chelsea missed out on a number of first-choice targets, including proven striker Romelu Lukaku who opted for Manchester United, while Diego Costa is expected to get his move to former club Atletico Madrid in the coming hours.

Merson believes that it is the outgoing activity that could cost the Premier League champions most, though, telling Sky Sports News: "Diego Costa isn't going to play for Chelsea again. The manager will lose face if he comes back.

"And they didn't get Romelu Lukaku, so the big question is who will get all the goals? They've got to hope the move for Alvaro Morata works. I didn't think they needed a lot and Antonio Rudiger and Tiemoue Bakayoko are good players.

"I would have given them a higher mark if they hadn't let Nemanja Matic move to Manchester United. I also wonder if Ruben Loftus-Cheek and Nathaniel Chalobah will come back to haunt them?"

Chelsea ended up spending the second-highest amount of any Premier League club following their final-day activity, handing over £202m in total.