Salomon Kalou believes that "anything is possible" when Chelsea face Barcelona in the Champions League semi-finals.
The Ivorian scored in Chelsea's 3-1 aggregate win over Benfica in the competition's last eight and they will now face the Spanish giants, who saw off AC Milan in their quarter-final tie.
However, rather than be fazed by the tournament favourites, Kalou is hopeful that the Blues can cause an upset and beat Pepe Guardiola's side in the last four.
"For most people Barcelona are the best team in the world, but in two matches anything is possible," said Kalou.
"I believe that in a Champions League match you can never underestimate an opponent. We saw Inter Milan with Jose Mourinho cause Barca trouble two years ago. We also played great matches against them three years ago.
"We know Barcelona well, but we must forget about the past. We are happy to have qualified and playing Barcelona will be a great challenge."
Kalou featured in Chelsea's 2-1 win over Benfica at Stamford Bridge on Wednesday night.