Chelsea suffered a 3-0 loss as they took on Brentford in the Premier League at the Gtech Community Stadium on Friday night.

Xabi Alonso's Chelsea headed into the international break with an embarrassing defeat at the hands of their west London rivals. They were thumped by Keith Andrew's side, who put on a stellar second-half performance.

There was little goalmouth action at either end in the opening 45. Chelsea's best chance of the half came from Pedro Neto; his left-footed strike was palmed out by Caoimhin Kelleher.

Morgan Rogers also had a pair of chances: a tame free-kick that was comfortably saved and a shot towards the back end of the half that was blocked by Jannik Schuster. The teams went into half-time goalless.

In the second half, the first chance fell to the hosts. Despite the offside flag being raised, Jaidon Anthony saw his header hit the crossbar.

While Chelsea got away with that one, at the hour mark, Anthony made no mistake. A corner was knocked back into his path, and he nodded home to give the Bees the lead.

Following the opening goal, the Blues started their search for an equaliser but mustered very few clear-cut chances. It was instead the hosts who doubled their advantage. Kevin Schade's effort was saved by Emiliano Martinez, but Igor Thiago was on hand to score.

Chelsea were thoroughly outperformed in the second half by Brentford. Their fate was sealed when Fabio Carvalho crashed in at the back post and made it 3-0.

Here are five things learned from Chelsea's loss in the Premier League against Brentford.

Chelsea started the season with back-to-back wins against Fulham and Brighton & Hove Albion, respectively, but they have stuttered since.

Following the 2-1 loss against Arsenal and the 2-2 draw against Hull City, the Blues failed to bounce back against Brentford.

A streak of three winless games in the league is not the way that Alonso would have wanted to head into the three-week international break.

There were encouraging signs defensively in the first-half for the Blues, but in the second half they were punished by Brentford.

Once again, Chelsea fell victim to poor defending from a set-piece. A simple corner undid the defence and allowed Anthony to head the hosts in front. Thiago's goal to extend Brentford's lead to two means the Blues have now conceded at least twice in each of their Premier League games under Alonso. The third goal from Carvalho rubbed salt in the wound.

The Blues have conceded a total of 12 goals in their opening five league games, the most in the league. The loss also ensures their hunt for a clean sheet continues,  as they are on a run of 22 games without one.

Chelsea's front three of Palmer, Rogers, and Pedro have been on fire to start the season. The trio have started all four games together, but this was disrupted against Brentford.

Following his withdrawal from the Brazil squad, there were question marks as to whether Pedro would be available for this game, but he was left out due to injury. 

Danny Welbeck was his replacement for this contest, but the Blues attack did not manage to click. Apart from a few half-chances, Chelsea created very little to trouble the hosts.

While Chelsea's recent performances are a cause for concern, the Alonso era has only just begun.

The Blues are clearly not the finished article yet; coming off a season finishing 10th makes it important to keep expectations realistic. This was a heavy defeat for Chelsea, and they rightly will face criticism. But there is a long way to go this season,  and the problems are not going to be solved instantly.  

The average age of the Blues' starters against Brentford was 27 years and 349 days, the oldest that Chelsea have fielded since May 2023 against Arsenal in the Premier League.

As well as 36-year-old Henderson earning his first start for the Blues, Pedro's absence for this contest handed 35-year-old Welbeck a place in the line-up. Of course, these two played a big role in bringing the overall age up.