The Scotland international believes that the Blues' current starting XI favour a passing game reminiscent of the Spanish giants.
"Now you are facing more Barcelona-like players. They have small, intricate players who get in the pockets behind you and they play killer passes. It is different to what we have faced but it will be a new challenge."
Fletcher is hoping to make his first start for United following a career-threatening bowel illness, and is targeting victory over Robert Di Matteo's side.
He added: "We do need a result at Stamford Bridge. It has been a while since we've had a win there in the Premier League.
"We know they are in great form in the league, but they lost in Europe this week, so that might help us a little bit. We have great confidence in ourselves and we will go looking for a win."
Manchester United take on Chelsea at Stamford Bridge on Sunday.