Rejuvenated by their interim manager and fueled by a desire for revenge, Chelsea's players have a growing belief they can down the mighty Barcelona in their Champions League semifinal against the defending champions.
Propelled by the magnificent scoring feats of Lionel Messi, the Spanish giants head to Stamford Bridge for Wednesday's first leg as heavy favorites to progress to their third final in four years.
Yet, Chelsea has rediscovered some of its old dynamic form since Roberto Di Matteo replaced Andre Villas-Boas as manager in March and has the experienced players to cause Barcelona problems.
"With Villas-Boas they played more from the back, keeping possession and having the initiative," Barcelona midfielder Cesc Fabregas said. "With Roberto Di Matteo they have compacted, the type of Chelsea that was successful a few years ago using counterattacks, more long balls and then using the number nine as a reference.
"I follow the Premier League and I think they are in their best shape at the minute. We have been very consistent as well. However in these games it is about winning, not the form you have had for the last couple of months. It is about trying to make it happen and getting Barcelona into a final."
Under Di Matteo, Chelsea has won nine and drawn two of its 12 games - and is coming into the first leg on the back of a 5-1 thrashing of Tottenham in the FA Cup semifinals on Sunday.
That record pales in comparison with the recent form of Barca, which has won 11 straight Spanish league matches and is unbeaten in 15 when including their pair of Champions League knockout-stage triumphs over Bayer Leverkusen and AC Milan.
Any thoughts of a possible final against fierce rival Real Madrid, which takes on Bayern Munich in the other semifinal, has been put to one side, however.
"All of our thinking and concentration should be on this game against Chelsea. If we think about anything else besides Chelsea, we'll be making a big mistake," Barcelona playmaker Andres Iniesta said.
"Chelsea was strong in 2009 (when the teams last met in the semifinals) and this year they will be very strong, dangerous and focused. And playing at their ground, the atmosphere will multiply that."
Iniesta has fond memories of that highly charged 2009 semifinal, with his spectacular injury-time goal in the second leg at Stamford Bridge sending Barca through on away goals to the final in which it would easily beat Manchester United in Rome.
Chelsea felt robbed in that second leg because of a series of perceived refereeing mistakes, and Frank Lampard spoke of the Blues having "unfinished business" to attend to after the jittery quarterfinal victory over Benfica.
"A long time has passed. I don't think they are playing for revenge," Barcelona coach Pep Guardiola said. "What you have lost, is lost. We will both be playing to try to reach the final in Munich."
Even with the galaxy of superstars throughout Barca's team, Messi continues to stand out.
The Argentina forward scored at the weekend for a record 10th straight league game to take his remarkable goal total this season to 63, the best since German great Gerd Mueller scored 67 in 1972-73.
Messi's haul of 14 goals in this season's Champions League has broken the competition record for one campaign, set by Ruud van Nistelrooy in 2002-03.
"What he's doing now, the levels he's taken his game to, is something I've never seen before," Lampard said. "I grew up with (Diego) Maradona - he was my idol. But I think Messi has taken it to probably further levels then him.
"To score the 70 goals he'll probably end up with this season, they're crazy figures."
The teams know each other well, having met 10 times in the past 12 years. In their four meetings in the knockout stage, Barcelona has advanced on three occasions.
"Discipline is a huge fact at this level," Chelsea midfielder Frank Lampard said. "To play a man down against Barcelona is very tough. We have to tackle and close space, but we've got a good discipline in our team. Keeping 11 on the pitch is crucial."
Barca has a must-win "Clasico" match against Madrid in the league on Saturday, but Chelsea's massive improvement in recent weeks will ensure Guardiola's team will focus on the here and now.
For its part, Chelsea may have to win the Champions League - for the first time in its history - to qualify for next season's competition. The London club is currently sixth in the Premier League with five games left to play.