Thomas Tuchel has urged “soft” Chelsea to toughen up after a shock 2-1 defeat by Southampton plunged his spluttering team into Premier League turmoil on Tuesday.

Tuchel’s side blew the lead at St Mary’s after Raheem Sterling put them ahead midway through the first half. Chelsea had squandered a host of chances before Sterling’s opener and, not for the first time in Tuchel’s reign, their profligate finishing came back to haunt them.

Romeo Lavia equalised in the 28th minute with his first goal for Southampton, curling home from the edge of the area after Chelsea failed to clear a corner.

Adam Armstrong put Southampton ahead on the stroke of half time as he took Romain Perraud’s pass and drilled a deflected shot past Chelsea keeper Edouard Mendy.

Chelsea, beaten 3-0 at Leeds in their previous away fixture, were unable to muster a response as they slipped to a second defeat from their last three games.

“Soft, soft, soft defending. There is no need to give shots away. Just toughen up as a team and show a different mentality,” Tuchel said.

“It is too easy to put us off balance, to beat us, to confuse us. It is too easy. It happened against Leeds. We need to understand why and find solutions,” Tuchel said.

“We lose concentration, we lose our plan and lose consistency. I don’t understand why we have so many injuries.

“In a match where you are in the lead there is no need to give away half chances. To have no answers in the second half was disappointing.

Watch Tuchel’s post-match conference: