Welcome to Flyertalk, hansvanheel...
But as this question is a little vague and I take it you would like to fly with any carrier, and not particularly with SQ, it does not belong here on the SQ forum.
So it shall be moved to a more appropriate forum.
Guy Betsy
Singapore Airlines Krisflyer forum co-moderator
RE: To your question, the fastest and shortest way might be with KLM. Direct flight via SIN to AMS and then transfer to MAD.