Benfica coach Jorge Jesus believes Chelsea are lucky to be ahead in their Champions League tie and is confident his side will eliminate the Blues on Wednesday.
Chelsea lead 1-0 from the first leg after Salomon Kalou's winner but Jesus has predicted his side will deliver a shock at Stamford Bridge and claim a place in the last four.
The odds are stacked against Benfica, with only two clubs ever having overturned a home defeat in the competition, but Jesus is confident of a turnaround.
"Chelsea obviously have the upper hand, but we are going to approach this game in the same manner as we would have if we had won the first game,'' he said. "Chelsea had quite a lot of luck in the first match, considering we dominated the match.
"We have the quality to win this game, obviously, and I'm sure that - this time round - we can turn the tables on Chelsea and do the same as they did in Lisbon.''
Jesus added: "They came out to play for a 0-0 draw and ended up getting a win. They'll be dangerous from set-pieces but we need to play an offensive game and cancel out that first-leg advantage. We'll go into this game being offensive.
"We need to score to progress, that's obvious, but we'll play an offensive game, an attacking game and I'm sure we can take it to Chelsea.''
Despite his confidence, Jesus could be forced to play holding midfielder Javi Garcia as a makeshift centre-half with captain Luisao a major doubt with a knee injury. "I have more problems than Chelsea ahead of this game,'' Jesus said.
As for Chelsea, Roberto Di Matteo has warned his side against complacency after their hard-fought victory in Portugal.
Chelsea became only the fourth club ever to overturn a two-goal first leg deficit when they beat Napoli to reach the quarter-finals, and need only draw the second leg to avoid becoming the third side to crash out after a first-leg away win.
"It is a danger," Di Matteo said. "This is half-time and we're leading 1-0, but a 1-0 lead is basically nothing. Our players are aware of this, and we'll have to go into this game with the right attitude, the same attitude as against Napoli.
"Nothing has been done yet. We're aware of that. We need to go and qualify for the next round.''
Benfica's limp performance at the Estadio da Luz contrasted sharply with those in their Champions League campaign as a whole, with Jorge Jesus' men having helped eliminate Manchester United in the group stage.
Di Matteo added: "This tie is far from over. They have scored in every away game of their Champions League season, so it's a difficult task tomorrow night.''