Chelsea’s season suffered a fresh setback with a disappointing defeat at Southampton, with Thomas Tuchel struggling to find a way to solve the issue that are plaguing them.

The Blues had actually gone ahead, when Raheem Sterling stayed cool to fire past Gavin Bazunu from close range. But the Saints stormed back into the game, with Roman Lavia scoring a stunner after a corner was only half-cleared.

And as the game entered first-half stoppage time, Adam Armstrong scored what proved to be the winner, with the Blues failing to find a way back into the match. Here, Mirror Football looks at five of the biggest problems facing Tuchel and Chelsea.

1. Goalscorer needed

Chelsea have plenty of creative players in their side, who are all capable of creating big goalscoring chances. But the draw at St Mary’s Stadium showed more than ever that they are crying out for a striker to finish those chances of.

Mason Mount, Raheem Sterling and Hakim Ziyech all had chances to open the scoring in the first-half. None of them were able to trouble Gavin Bazunu in the Southampton goal though, until Sterling’s opener.

Raheem Sterling scored against Southampton, but Chelsea are still crying out for a goalscorer

The fact it took the Blues four good chances to finally score will be a concern to Tuchel, given his side will come up against much tougher defences. With  Manchester City, Arsenal and Liverpool all having bought out-and-out scorers this summer, the Blues may need to follow that example.

2. Aerial struggles

Perhaps surprisingly for a team known for their modern style of football, Southampton set up to target Chelsea in the air as much as possible. Gavin Bazunu’s kicks forward tended to be aimed towards Che Adams.

Adams mainly set himself to go up against Thiago Silva and proceeded to win six of his aerial duels. Silva eventually took the decision to not even challenge Adams in the air, with the Saints star so dominant.

That forced Chelsea onto the backfoot, with Southampton improving at picking up Adams’ flick-ons as the game went on. The Saints also deployed the use of a long throw to cause mayhem in the Chelsea box, with the Blues struggling to deal with that threat.

3. Tuchel still searching for best system

Thomas Tuchel is struggling to find his best system at Chelsea

Tuchel opted to continue with the four-man defensive system that helped his side to beat Leicester on Saturday. But the Blues looked far from their true selves on the South Coast, with Southampton enjoying plenty of attacking joy.

While Chelsea had plenty of verve when going forward, they looked remarkably open at the back. The hosts had several big chances of their own, with the visitors forced to scramble back frequently.

Much of that could arguably be down to the lack of pace in defence, with all but one of their backline being over the age of 30. That lack of pace was exploited by Southampton and will leave Tuchel pondering if four at the back is the right way to go.

4. Lack of impact off the bench

Tuchel made four of the five changes he is permitted, but none of them had the desired impact on proceedings. First Mateo Kovacic replaced the injured Ruben Loftus-Cheek, though the Croatian struggled to get himself into the game.

The Blues boss then made a triple change with 24 minutes to go, which saw the visitors switch to their traditional 3-4-3 formation. Again though, that did little to inspire a change in situation, with Southampton looking far the better side through the second-half.

5. Mendy issue

Edouard Mendy again struggled in the Chelsea goal

The questions over Edouard Mendy are continuing to stack up with the keeper facing more criticism for his performance at St Mary’s. While Romeo Lavia’s goal looked to be a stunning one at first viewing, Mendy did get a big hand to his shot.

But the ball bounced off his glove and into the net for Southampton’s equaliser. In fairness, the Frenchman did have little chance to save Adam Armstrong’s shot for the Saints’ second goal.

His struggles between the sticks are a huge concern for Tuchel though, who have Kepa sitting on the bench. The Chelsea boss may need to consider bringing the Spaniard into the starting line-up if Mendy’s struggles do continue.