Chelsea lost 2-1 against Southampton on Tuesday, and there were plenty of culprits.

If Thomas Tuchel wasn't concerned before, Tuesday night's performance will provide plenty of reasons to worry as the Blues continued a lacklustre start to the Premier League season.

Chelsea were deservedly beaten 2-1 by Southampton as goals from Romeo Lavia and Adam Armstrong cancelled out an opener from Raheem Sterling. The loss is Chelsea's second in three games, having previously been blasted 3-0 by Leeds before a narrow 2-1 win against Leicester.

The Blues looked a step off the pace, with Southampton trampling an overrun Chelsea midfield trio. The absences of Reece James, N'Golo Kante and any sort of No. 9 were felt on a night to forget for Tuchel and his players.

With the loss, Chelsea now have just seven points through five games and are in danger of falling out of the title race.

Sterling was wasteful at times particularly in the first half. The winger squandered several chances, one of which fell apart due to his own selfishness.

But he should get credit for creating those opportunities, and he did put one first-half shot into the net.

Sterling scored Chelsea's lone goal, a scrappy finish to cap off what was a beautiful move leading up to it. Mason Mount's ball across goal was pushed out to Sterling, who took advantage of a slow-to-react defence to turn and fire.

The former Manchester City winger was the only Chelsea player whoo was truly threatening, and the only attacker who seemed to be matching the pace of the game.

What a moment for the former Manchester City youngster!

Lavia hit an absolute missile to level the score, digging Southampton out of a hole soon after Sterling had taken the lead.

Lavia became the first player born in 2004 to score in the Premier League - not bad for the teenager, who has hit the ground running at Southampton to start the season.

Manchester City essentially have to let players like Lavia go sometimes, as minutes are hard to come by for youngsters in Pep Guardiola's machine. But they'll certainly be keeping a close eye on the midfielder as he continues to prove he's more than ready for England's top-flight.

Deadline day is nearly here, and Chelsea look like a team that will need some help.

As they faltered in Southampton, reported target Anthony Gordon starred in Leeds, scoring a lovely goal for Everton as rumours swirl. The young winger would be an expensive buy for the Blues, who, despite their attacking talent, have really struggled to convert in front of net.

Pierre-Emerick Aubameyang has been linked for similar reasons, while Wesley Fofana and Josko Gvardiol could come in to provide more options at centre-back.

It remains to be seen if any of these players come in before the window shuts, or how much they'll cost if Chelsea do pull the trigger. But, so far this season, the Blues have looked like a team that will need to do a bit of business if they hope to compete at the top of the table.

Prior to the match, with both teams waiting to march onto the field, Azpilicueta was mocked by a young Southampton mascot. It was a light moment that broke the tension pre-match, and it also proved to be the only bit of fun on the day for the Spanish defender.

Azpilicueta looked his age in this one. The 33-year-old defender struggled on the right-hand side, where he started in place of Reece James, who was out sick.

He conceded the corner that led to Southampton's first goal, and then mis-hit his clearance right to Lavia for the youngster's fine finish. In general, Azpilicueta struggled with the pace of the game as James' presence was sorely missed.

The England star is irreplaceable these days as questions remain about Azpilicueta's ability to truly back him up as a pure right-back.

For years, Tuchel's preferred formation has included three centre-backs, and nights like this show why.

Chelsea simply don't have the personnel to play in a four-at-the-back system right now, as the midfield left the backline exposed too often.

Jorginho struggled defensively and cannot play as a pure No. 6 without some sort of cover. Loftus-Cheek had a promising start, but was then far too predictable on the ball after the first few minutes, proving a detriment as the game wore on. And Mount did well enough, but obviously doesn't offer as much of a defensive presence.

Do Chelsea need a stronger presence like Declan Rice? Quite possibly. Would a healthy N'Golo Kante mask these sorts of problems? Maybe. Are they better suited for a three-at-the-back system? Most definitely.

It was a night to forget for the Blues' midfield.

The American was benched for the fifth consecutive game as transfer rumors continue to swirl.

Recent reports say that Pulisic will not leave Stamford Bridge, despite links to a loan move to Manchester United. He will instead be asked to fight for his place with Tuchel unwilling to let him go.

All of that, then, for him to just be thrown into the game out of position after the team's initial setup didn't work.

Pulisic is not a wing-back, and while it is nice for him to get onto the field, minutes in that part of the pitch don't help anyone. After coming on in the second half, Pulisic struggled, turning the ball over twice early and never really making much of an impact from where he was on the field.

It doesn't look like he'll leave, and that will likely be frustrating for a player who can't seem to ever get onto the field in his preferred position.

Was unhappy to concede after getting a hand to Lavia's rocket of a shot, but there was nothing he could do on the second.

Relatively quiet night as he never really got involved.

Returning to the line-up, Koulibaly has just seemed off since coming to London as he misplaced several passes.

The best of the bunch in defence, made a vital goal-line clearance that prevented Southampton from extending their lead.

Conceded the corner and then failed to clear on Lavia's goal. A bad day for the Spaniard.

Set up Chelsea's opener, but didn't do much other than that.

Too slow and too weak defensively to play in this system.

Ten good minutes and then 35 bad before being taken off at half-time.

Hit a few lovely passes, but never really threatened.

Was essentially nonexistent in the attack. Does he have a position in this team?

Not great, but not bad as he created chances and got his goal.

Nothing spectacular, but certainly improved the midfield after coming on.

Struggled with several bad giveaways that aren't exclusive to what position he's in.

Facing his former club, showed more in attack than Havertz did.

Decent in his limited minutes.

Didn't set his team up to win as a slow Chelsea team showed its age in a back-four.