Bacary Sagna has claimed that he and Manchester City teammate Eliaquim Mangala were not in the right frame of mind to play in Saturday's 4-1 defeat at home to Liverpool.

Mangala conceded an own goal after eight minutes and looked shaky for the remainder as the Reds capitalised on a lacklustre defensive showing.

The French defenders were on international duty when a suicide bomber killed three people outside the Stade de France during Les Bleus' friendly with Germany 10 days ago.

At least 130 people have since been confirmed dead following the terror attacks on Paris that night, and right-back Sagna concedes that he and Mangala were left shaken by the tragedies.

"It's not my best week. But it's life and there's nothing you can do about it. It's part of the past now and you just have to keep your head up," he is quoted as saying by The Guardian.

"It was not easy to be part of that event [in Paris]. Mentally I was ready to play. Physically I believed I was. But I wasn't. I tired quite quickly.

"It was quite difficult [for Mangala too]. We started the game really well but we conceded a goal quite quickly and we were both involved in the first goal so it's never easy [after that]. We had to keep our head up and that's what we are going to do in the future."

Philippe Coutinho and Roberto Firmino helped the visitors into a shock 3-0 lead after Mangala's own goal.

Sergio Aguero pulled one back before the break, but Martin Skrtel restored the three-goal cushion in the final quarter.