Leicester manager Nigel Pearson believes his side are capable of causing a FA Cup upset at Stamford Bridge this weekend.
The Foxes travel to west London for the sixth-round tie on Sunday, having already won away at Barclays Premier League opposition in this season's competition after beating Norwich in the previous round.
Pearson is no stranger to cup runs and reached the FA Cup final with Middlesbrough in 1997, losing 2-0 to Chelsea.
That Blues side contained current caretaker manager Roberto Di Matteo, who scored the opening goal which whizzed past Pearson's head after only 42 seconds.
Pearson said: "Due to the nature of knockout competitions, anything can happen on the day.
"We have to go into the game with a very positive mindset and make life difficult for them, so of course I believe we can move forward. Although, clearly we have to catch them on a not so good day and we have to be at our best.
"I have been very fortunate to be involved in some very successful cup runs in my career as a player.
"The key factor for us is that our players have to go out there and see it as an opportunity to play against a side who are, and have been for the last few years, one of the most successful teams in the country.
"We want to go and give a good account of ourselves and cause some problems. We will approach the game in a positive manner, but we also know we have to be wary of the talent they have. You have to respect the opposition.
"I still think it is a fabulous opportunity for the players to show what they can do and we have earned our place in the quarter-finals."
Leicester teenager Jeff Schlupp has spoken this week of his dream to start at Stamford Bridge, and hopefully play against his Ghanaian idol Michael Essien.
Schlupp scored his sixth goal of the season on Tuesday night during the npower Championship victory over Birmingham, who held Chelsea to a 1-1 draw at Stamford Bridge in the previous round before losing the replay 2-0.
It was the 19-year-old's first strike since returning from seven weeks out with a knee injury and Pearson acknowledges that the striker is ready to start more games for the Foxes.
"The reason we recently extended his contract is because we feel he has the potential to go on and be a very good player but, with any young player, I think it is important to nurture them," said Pearson.
"He has a lot of very good attributes for a striker. He will get better with experience and I think he will get the right level of exposure from us.
"He is not that far away from a starting position but, against Birmingham, he showed what he can do coming off the bench as well. Not only did he finish his chance well, I think his hold up play was very good too. He gives us a good option."
Leicester are hopeful Lee Peltier will recover from a thigh injury after he missed the Birmingham game, while fellow defender Paul Konchesky will come back into the reckoning after suspension.