The Blues were stunned at the St Mary's on Tuesday night and picked up an unwanted milestone in the process.

Chelsea manager Thomas Tuchel has hit out at his side's defending and mentality following Tuesday night's Premier League defeat at Southampton. The Blues were on the wrong side of a 2-1 scoreline as they picked a second successive defeat in the new season.

Ahead of the encounter, Chelsea were unbeaten in their last 9 games away to Southampton and had won seven while drawing twice on the South Coast. With the omen well in their favor, the Blues showed signs of promise and were duly rewarded through Raheem Sterling's opener in the 23rd minute. However, the lead was rather shortlived as the Saint's new-boy Romeo Lavia will restore parity less than five minutes later.

Right on the stroke of half-time Adam Armstrong slotted home what would be the eventual winner to put Southampton in the drivers seat. Chelsea strived to get a sufficient response in the second half but could not fashion any as they slumped to their second defeat of the season.

So far, Thomas Tuchel's men have taken just seven points from their first five games; and, following the conclusion of Tuesday's affair, the German coach was quick to call out the toughness of his players as well as their overall mentality. "We are not tough enough to win these matches away," he said in his post-match press conference.

"Today, we scored so everything was okay but one set piece again, one sloppy defending again, we were off-balance and we did not react to it. We were lucky not to concede a third goal at the beginning of the second half. We were not tough enough as a team to react or push it over the line for us.

"Soft defending. What stops that is pure mentality, stop it with defending mentality. There is no superiority for the opponent, there is no need to give shots away, just toughen up as a team and show a different mentality.

"I don't like to talk about it normally because you cannot prove it with data or tactical position but it is like this," Tuchel added.

"Both goals are cheap, soft goals and should not happen if you expect to win a match in the evening at an away stadium."

For Southampton, Tuesday's 2-1 win over Chelsea was their first at home since mid-April. The result saw the Saints leapfrog their opponents into seventh after just five matches.