Two horrible Branislav Ivanovic errors gave Swansea a huge advantage in their Capital One Cup semi-final with Chelsea after a 2-0 first-leg win at Stamford Bridge and put more pressure on Rafa Benitez.
The defender's failure to control a ball on the edge of his own penalty area gave Michu the chance to open the scoring in the first half against the run of play.
Chelsea, who started with Fernando Torres instead of January signing Demba Ba, dominated but Danny Graham made it 2-0 in injury time when pouncing on Ivanovic's blind back-pass.
The European champions had a claim for a penalty, which saw Ba booked for diving, immediately before Graham's goal in a dramatic conclusion to the game.
But interim boss Benitez heard his team booed off at the final whistle and they must now overcome two away goals in the second leg.
Chelsea's fans spent a large chunk of the match berating Benitez for his failure to bring on Ba, who scored twice on debut last weekend, and they also took umbrage with the interim boss' failure to bring on Frank Lampard until the 70th minute.
The Blues dominated the game, but lacked a killer touch up front and they paid the price in the 39th minute when Ivanovic's blunder gifted Michu the chance to score his 16th goal of the season.
David Luiz, by far Chelsea's best player, went close with two efforts just after the break but the home fans continued to vent their anger at Benitez for not introducing Ba or Lampard.
One fan had to be restrained by stewards as he headed in the direction of the Chelsea bench to remonstrate with the former Liverpool boss.
Another fan invaded the pitch to provide the Blues fans with some entertainment. The rest of the home crowd continued to demand Lampard's introduction but the calls fell on deaf ears.
Lampard injected life in to the Chelsea team but Torres continued to perform poorly. The striker found space on the edge of the box, but could only head weakly in to Gerhard Tremmel's arms.
Ba was sent on in place of Torres in the 81st minute and hurtled through in injury time, going down after Tremmel failed to collect the ball in the penalty area, but the referee did not give a penalty and instead booked the former Newcastle United man for diving.
Chelsea's night then turned from bad to worse with one minute of added time left. Ivanovic's second terrible back-pass allowed Graham to pinch the ball off Turnbull before slotting in to an empty net while Ba's later disallowed effort for offside only added to the frustration.
1st Half Goals
Shots on Target
Shots off Target
1st Half Poss.
2nd Half Poss.
Inter president Massimo Moratti is willing to allow the unsettled Dutch midfielder to leave but any deal will depend upon the Turkish club reaching an agreement with the player.
"Galatasaray's offer satisfies us. Now it depends on the player," Moratti told Sky Italia.
"We would be happy if he decided to stay on our terms."
Sneijder has reportedly been asked to accept a two million euro pay cut to his annual salary with the Nerazzurri.
But Inter head coach Andrea Stramaccioni continues to maintain that the 28-year-old's absence from the first team is purely a tactical decision.
Sneijder is believed to be holding out for better offers from a host of Premier League clubs as well as big-spending Ligue 1 outfit Paris St Germain.
On Wednesday, Sneijder's agent, Soren Lerby, refused to confirm Gala's claims that they had opened talks, telling De Telegraaf: "Every day there is a new club linked with Wesley.
"For that reason I have decided not to answer any more questions."
But a statement on the Turkish club's official website read: "Galatasaray announces it has begun negotiations with FC Internazionale for the transfer of Wesley Sneijder.
"The public will be informed of developments."
The former Manchester City striker, who took over in the summer of 2011 and has guided the Bees to fourth in League One, has committed himself to the club until May 2015.
He told the Bees' official website: "It is very exciting to be part of Brentford Football Club.
"There has been a lot of progress made in the past 18 months.
"I have seen commitment from sporting director Mark Warburton, from backroom staff who have been approached to move to Championship clubs and who have opted to stay with us, and from players who are signing new contracts.
"It was a no-brainer for me to stay here and be part of an exciting future for the club.
"I can see the commitment from the owner and the board of directors to take the club where we want to take it. And that is not just short-term commitment.
"It is an honour and a privilege to lead the club for the next two years.
"The club has moved on enormously in the past 18 months, in all areas.
"We have changed the playing squad almost entirely and results are going in the right direction at the moment."