Xabi Alonso said Chelsea are currently not consistent enough to compete with Premier League rivals for the full 90 minutes, after they were thrashed 3-0 by Brentford.

Having started their first campaign under Alonso impressively with back-to-back wins over Fulham and Brighton, the Blues are now winless in three league games.

They made the short trip to the Gtech Community Stadium off the back of a 2-1 defeat to Arsenal and a 2-2 draw with Hull City, and they were without August's Premier League Player of the Month, Joao Pedro, after he sustained a knee issue.

They combined a lacklustre attacking performance with some rookie defending in the second half as Brentford ran out comfortable winners, with the goals coming from Jaidon Anthony, Igor Thiago and Fabio Carvalho.

The 12 goals Chelsea have conceded this season are the most in the Premier League, ahead of the weekend's fixtures, while they have also given up the most expected goals against (8.82 xGA). 

Speaking to Sky Sports afterwards, Alonso said: "I'm disappointed with the second half and with the result. This is not enough to compete in the Premier League.

"We were not able to maintain our level for the full 90 minutes and that's why we were punished today.

"At the moment, we are not consistent enough to compete throughout the whole game – 45 minutes is not enough. 

"You need to maintain it for the whole game, knowing that every detail is important, and every action can be decisive."

Alonso is only the sixth manager to see his side concede multiple goals in each of his first five games as a Premier League manager, after Mick McCarthy, Sammy Lee, Terry Connor, Slavisa Jokanovic and Scott Parker.

Asked how Chelsea could plug their leaky backline, he added: "It's about everything. 

"It's about the mentality, the football and the tactical things that we need to keep improving. We can do much better."

Alonso also refused to use Joao Pedro's absence as an excuse for Chelsea only managing two shots on target and 0.85 expected goals, compared to Brentford's six efforts on target and 2.65 xG.

"It's not about looking for excuses. We need to look at each other and know that we have to work and improve because there is still a long way to go," he said. 

"We have to check many things. We got into situations, but we were not precise enough with the final action. That's why we didn't score."

One bright moment for Chelsea on a bleak evening was a late cameo from Mahdi Nicoll-Jazuli, who became the first player born in 2010 to play in the Premier League and the first 16-year-old to represent Chelsea in the competition.

Chelsea now have more than three weeks to stew on their defeat over the extended international break, with Bournemouth their next opponents on October 10.