Athletic drew 1-1 at home to struggling Sporting Gijon on Sunday after they conceded a last-minute equaliser. The La Liga side also missed a first-half penalty through striker Iker Muniain.
Schalke pose dangerous goal-scoring threats in the form of Raul and Klaas Jan Huntelaar, but having already dispatched Manchester United in the round of 16, Susaeta believes Athletic can harness that form against the side currently third in the Bundesliga.
"If we play like we know we can, like we did in Manchester for example, I think we have a great chance of getting a good result and then here, at San Mames, we will try to get through," Susaeta said.
"It would have been normal to win that game (against Sporting) 2-0 or 3-0, but when you don't make the most of your opportunities you pay.
"And if you waste chances and facing you are world-class goalscorers, like Huntelaar and Raul, and they have one opportunity, they will finish you off.
"It's clear that we cannot waste chances like against Sporting."
Athletic coach Marcelo Bielsa is without the injured David Lopez, Aitor Ocio, Carlos Gurpegi, Xabi Castillo and Igor Martínez for the trip to Germany.
Schalke goalkeeper Timo Hildebrand is cautious of Athletic's threat following their 3-2 win over Sir Alex Ferguson's Manchester United in the previous round.
"We need to be wary as they are very strong and versatile in attack," Hildebrand told the club's official website, www.schalke.de.
"Overall, Spanish teams are technically very good. Bilbao is a very strong opponent, which has already put a strong opponent in Manchester United to the test in the second round.
"On the other hand, we are also currently in very good shape and want to confirm that in the two games, against Bilbao.
"If we use the self-confidence we have as we did against FC Twente or even Leverkusen, we can decide the result on Thursday."