The Bundesliga club shocked holders Inter Milan in the quarter-finals and are convinced that drawing Sir Alex Ferguson's side has given them a better chance of going through to meet Barcelona or Real Madrid in the final at Wembley on May 28.
Centre back Christoph Metzelder summed up Schalke's growing confidence ahead of the first leg, saying: 'Of course we know that Manchester United have so many key players but they don't scare us.
I'm a believer! Christoph Metzelder is confident Schalke can reach the Champions League final
'It would be much more difficult for us to play against Barcelona. They get control and make you run so much it's very difficult to defend against them. The style of Manchester United is easier for us.
'United are big favourites but it suits us being underdogs. United will have respect because if you qualify for the semi-finals then you have to be a good team.
'Our coach is very intelligent, he analyses our opponents and is very self-confident.'
Schalke's new boss Ralf Rangnick masterminded the stunning 5-2 win over Inter at the San Siro and a 2-1 victory over the Italians in the second leg in Gelsenkirchen.
One of us: Schalke's Raul celebrates with supporters after the win over Inter Milan
Rangnick believes he has identified weaknesses in United and is not concerned that the Premier League leaders have only conceded three goals in Europe all season.
'It's about time that they conceded more goals,' he said.
'If you watch any team in the world you can spot weaknesses. We're not aiming for a 0-0. We want to win the game and will certainly play as we did against Inter at home.'
Billed as a shoot-out between United striker Wayne Rooney and Raul, Metzelder admitted he is wary of the United striker, but says the Champions League all-time top scorer could be Schalke's trump card.
'Of course, Rooney is the key player,' said the German defender. 'But Raul is a big weapon because he's someone who is always successful. Wherever he plays he wins trophies.'
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