The hosts otherwise began the match quite well, where midfielder Thomas Jorgensen, who spent a season with FC Copenhagen two years ago, posed a constant threat.
However, a terrible goalkeeper blunder by Viborg's Lucas Lund spoiled the promising start after half an hour.
Lund lost a poor finish from FC Copenhagen on the ground, and then FC Copenhagen's Youssoufa Moukoko had an easy job to poke the ball into the net.
Thomas Jorgensen continued to orchestrate things in the Viborg midfield, and soon after, it translated into a goal on the scoreboard. Jorgensen took matters into his own hands and launched a terrific curling stringing drive from outside the box to leave FC Copenhagen's Icelandic keeper Runar Alex Runarsson helpless.
The second half was just 50 seconds old when Moukoko again turned into a personal nightmare for Lucas Lund. The German striker took the chance from the edge of the box, but even though the finish was not hard or well-placed, Lund could not prevent the ball from hitting the net, even though he got a touch to it.
Viborg pushed forward in the final phase with the Copenhagen visitors happy to defend deep, but Jacob Neestrup's side stood firm to earn their ticket for the Cup final, where they will meet the winner of FC Midtjylland vs. AGF.
