Benfica ace Pablo Aimar insists Chelsea are not clear favourites to win their UEFA Champions League quarter-final clash.
The Argentina international midfielder will look to be the catalyst for a Benfica success as they host Chelsea in the first leg of their tie on Tuesday in Lisbon.
And Aimar insists confidence is high in the Estadio da Luz of securing victory over the Premier League club.
"I do not consider anyone to be clear favourite in this tie," he told Sky Sports.
"The situation is very open and either side could go through.
"The club that gets through to the quarter-finals has not done so by luck, both Benfica and Chelsea have earned their place here."
Aimar admits that Chelsea are hard to predict after an up-and-down season, adding: "Chelsea are developing an irregular season, but English clubs are always very dangerous and they will create problems in this match for us.
"But Chelsea have weak points in the team, but we prefer not to speak about our rivals. They have an enormous squad and it is almost like a final for us.
"Benfica, though, is playing very good at the moment. If we can practice our normal game then we can win but we need a big effort on the pitch."
The game sees both David Luiz and Ramies return to the club and Aimar is looking forward to facing his former team-mates.
"I have an excellent opinion of both David Luiz and Ramires from their time at Benfica," he said.
"They were good friends and good professionals."