Head coach Graham Potter has acknowledged that Chelsea 'took a step backwards' as they lost 1-0 to relegation-threatened Southampton on Saturday afternoon.

Chelsea started the week on a four-match unbeaten streak, albeit with three successive draws, but that came to an end on Wednesday night as they succumbed to a 1-0 defeat to Borussia Dortmund in the Champions League.

Despite that setback, there were positives to take from the Blues' performance at Westfalenstadion, with chances being created and missed rather than Potter's side not looking a threat in the final third.

However, all momentum has now been lost with Chelsea succumbing to defeat to bottom-placed Southampton at Stamford Bridge, James Ward-Prowse's free kick just before half time proving to be the difference to leave the West Londoners in 10th position in the standings.

On another day, Chelsea would have claimed a share of the spoils after a much-improved second-half display, yet it will be their ineffective opening 45 minutes which will concern supporters.

Potter made six changes from the team which started in Germany, handing complete rests to Reece James, Thiago Silva, Ruben Loftus-Cheek and Hakim Ziyech, and choosing to hand other squad members game time after injury.

Those decisions played a part in a poor start to proceedings, and Potter hinted after the game that he regretted some of the calls that he made.

Speaking to reporters at a press conference, as quoted by football.london, Potter said: "Certainly in the first half, it was a below-par performance. Returning from the Champions League and we had to make some changes, so you lose a bit of fluidity and cohesion.

"Southampton set up with a plan, an idea. They mixed the game well with a big target man but our performance wasn't what we wanted in the first half and I take as much responsibility as anybody in that.

"I thought the response second half was good and I thought we deserved a goal, we created enough chances to score. But when you don't, then obviously it's difficult to win matches."

A head injury to Cesar Azpilicueta overshadowed the match, the defender being kicked in the face by Sekou Mara when he attempted to score with an overhead kick.

Potter revealed that the club legend was taken to hospital, where he is conscious, with all precautions being taken after eight minutes of on-pitch treatment were required.