LONDON, England -- In the space of 10 minutes, Chelsea went from being in the familiar position of a goal to the good at home, to wondering if their season is going to unravel.

Antonio Rudiger's wondergoal at the start of the second half brought relief at Stamford Bridge, but it was only a momentary respite from the off-field ownership battle and now on-field uncertainty engulfing the club. What followed was a brutal exposure of the hosts' fragile state as Christian Eriksen, Mads Roerslev and Bryan Mbuemo orchestrated a historic 4-1 win for Brentford.

Three times Brentford hit Chelsea on the counter-attack from the 50th to the 60th minute with Vitaly Janelt striking twice either side of Eriksen's first Premier League goal for the Bees. Yoane Wissa grabbed a fourth in the dying embers of the game to guide them to their first win since 1939 over their London neighbours -- just 5.5 miles lie between Stamford Bridge and Brentford's ground.

In their first season in the Premier League, this was Brentford's biggest win of the campaign, and one of the most impressive in the club's history. It was orchestrated through hustling, high pressing and being brilliant nuisances to Chelsea. There was scant respect for their traditional bigger brothers. Instead Thomas Frank's side got their tactics spot-on as Chelsea struggled to break the high press, leaving Brentford poised to counter-attack whenever Chelsea's desperation left them exposed at the back.

Mbuemo was the one out-ball for Brentford, but it all went through that midfield maestro Eriksen. In his four starts for the club they have won three -- no wonder Frank is desperate to keep the Danish midfielder beyond the end of this season.

"Christian is a top player," Frank said Saturday. "He's an ongoing fairytale and I'm very pleased for that. He's calm on the ball, he finds a solution, and he provides goals and assists."

The win for Brentford puts them 11 points above the relegation zone, and while they can start to plan for next season, Chelsea's immediate and distant future remain uncertain. With the club up for sale, four bids remain ahead of the April 11 deadline.

"We gave away three goals in 10 minutes, which is untypical. I don't know why we did it," Chelsea manager Thomas Tuchel said afterward. "We didn't defend mature enough and it was very strange for us. We got punished. It's a summary of strange events. It was a tough start for us -- we felt a bit leggy, which is normal. Normally the goal is exactly what we wanted to open up new spaces but the opposite happened, and I don't know why."

The build up to the match was dominated by talk of who their potential owners will be and the controversy caused by the Ricketts family bid to buy the club. Earlier on Saturday the Chelsea Supporters' Trust declared its membership "neither supports nor has confidence in the Ricketts' family bid for the club." In a CST survey, they said 77% of its members did not back the Ricketts' bid.

This was in response to comments made by patriarch Joe Ricketts in a leaked email exchange several years ago that "Muslims are naturally our enemy." It has been three years since Joe Ricketts apologised after online media outlet Splinter News published emails featuring him making anti-Islamic comments, such as Islam is "a cult and not a religion.''

On Saturday, the Ricketts family issued a statement saying "diversity and inclusion" were at the heart of their bid for the club, but judging by the 100 or so group of fans outside the stadium protesting their bid (several banners reading 'No to Ricketts') and the CST statement, they're a way off convincing the Stamford Bridge faithful of being the right custodians of the club.

Tuchel asked pre-match for supporters to make their feelings clear outside the ground, and not during the match so as not to "distract" the team. He said prematch the team "were not affected" by the protests, but still it was a little eerie outside the stadium with the giant merchandise shop shut, and souvenir vans lying empty.

Although the protests remained outside the stadium, Chelsea looked rattled early on -- Brentford could have had two in the first 10 minutes with Ivan Toney causing all sorts of bother -- and though Chelsea rallied to pepper David Raya's goal with some well-struck efforts, it needed Rudiger's thunderbolt of a drive (conservative estimates put it at about 35 yards) to break the deadlock.

Lesser teams would have buckled having gone behind, but Brentford used it as the fillip to go up another gear and Janelt struck the equaliser just two minutes later. Mbuemo then picked out Eriksen to finish from close range for their second, and Janelt chipped in a third over Mendy -- who had struggled with a knee injury throughout the match -- to make it 3-1.

"We timed it perfectly to score the four goals in front of our fans," Frank said. "In football you work so hard, so many hours, every day, every week. Sometimes you don't get what you deserve, but today everything clicked. Winning here at Stamford Bridge against the European champions, that was almost a complete performance. What I like is that we were brave, pressed high -- it was a big moment for the club."

As quiet as the Chelsea fans were, the Brentford supporters were lapping it up in their corner of the stadium. They went through their full repertoire of songs, and the third brought the first rendition of "We're just a bus stop in Hounslow" -- a self-deprecating song referring to previous bating from Queens Park Rangers fans.

Then Brentford added the wonderfully-struck fourth in the 87th minute through substitute Wissa. They're on the map now, but keeping Eriksen is key to developing this team.

Chelsea, meanwhile, are riddled with uncertainty. The off-field ownership picture should become clearer by the end of the month, but that may be too late to keep their defensive spine together and season on-track.

With Andreas Christensen reportedly on the verge of joining Barcelona, Rudiger also out of contract and Cesar Azpilicueta's future uncertain despite the club triggering an extension clause in his contract, there are far too many distractions for Tuchel to feel comfortable as they plan for another huge match on Wednesday. And that's on top of the underperforming Timo Werner, a poor performance from Marcos Alonso, and those endless errors.

"It seems like another blip. I would refuse to make a drama out of this," Tuchel said Saturday. "Why should we? Brentford made a lot of the 10 minutes we gave them. After the third goal we had a disallowed goal and then we had a big, big chance from Kai Havertz and we missed them. It's a mixture of everything, but I would not rely on that to be destiny. We'll find out why it was like this, we will analyse, digest -- it's unusual for us and hard to take. We will refocus on Monday."

With Real Madrid coming to town in the Champions League quarterfinals this week, and Crystal Palace up in the FA Cup semifinals on April 17, Tuchel needs to get this team back on track. Chelsea looked sluggish with misplaced pass after pass.

By the time Wissa struck Brentford's fourth, Chelsea's supporters were already streaming for the exits. With blue seats dotted around Stamford Bridge and Brentford fans chanting "We want five" ringing in the Chelsea players' ears, Tuchel shook Frank's hand and headed straight down the tunnel at the full-time whistle. He will hope this result was a mere blip rather than the start of the season falling apart.