Striker is confident his side will encounter no great difficulty in making their way past Sir Alex Ferguson's men, and hopes to meet Real Madrid at Wembley
The German club eliminated current holders Inter, who bowed out after being on the receiving end of a 7-3 aggregate.
Now the Peru international is hoping to make it past the Red Devils and set up a date with Real Madrid, as he believes Barcelona would present an unwanted complication.
"Schalke won't have any problems with United and can get to the final," Farfan said, according to The News of the World.
"I'd love to face Real Madrid there as Barcelona would complicate matters."
The former PSV Eindhoven striker also conceded that he would have preferred to have a go at Chelsea, but insists that there is no lack of confidence ahead of the first leg against Sir Alex Ferguson's charges.
He said: "I still can't believe we're in the Champions League semis. It's a dream for us and especially me, having not been able to play against Inter. I would have preferred Chelsea in the semi-finals but we are still confident."
Manchester United lock horns with Schalke in the fist leg of the semi-finals of the Champions League on Tuesday in Germany.
Our provides the best breaking news online and our football fan community is unmatched worldwide. Never miss a thing again!