Brazilian keeper Helton is confident that Porto can eliminate Chelsea and go on to win the UEFA Champions League this season.
The Portuguese side last won Europe's biggest club competition in 2004 under the supervision of Jose Mourinho, but their former leader now stands in their way of a place in the quarter-finals.
The Blues boss will return to Estadio do Dragao on 21st February for the first leg of the last 16 tie, and if reports in the English press can be believed then this season represents Mourinho's last chance of winning the European Cup with Chelsea.
The London side are currently suffering a poor run of form in the Premiership - with speculation suggesting that Mourinho is ready to leave in the summer - and Helton feels Porto can take advantage by eliminating The Blues from Europe.
Moreover the goalkeeper - who has been selected in Brazil's squad to play Portugal on 6th February - is not ruling out Porto emulating their shock victory in 2004 by triumphing in Athens in May.
"People have made the English club favourites but I am always optimistic and I am convinced that we can surprise," said Helton.
"I do not rule out winning the Champions League because this team is desperate to succeed on the field."
Helton is also hoping that 2007 brings him a number of opportunities under Brazil coach Dunga, but Porto team-mate Pepe is unlikely to join him with the Samba stars.
Portugal have designs on the defender and hope to entice him to play for the European country in a similar vein to the way Deco opted to work under Luiz Felipe Scolari in 2003.
"He is a big player and at this moment we are studying this question," Portuguese Federation president Gilberto Madail told Lusa.
"The decision is down to the Federation and not only the coach. Scolari knows our plans and has received the instructions to respect them.
"The interest of the national team is key. With Deco the result was not negative."