Andy Whing’s team eased to a stylish semi-final win at the Hive and will meet either Bromley or Altrincham under the Arch next Sunday.
They didn’t look back once James Clarke headed them in front on six minutes.
Jack Stevens doubled the lead on the counter attack before Tahvon Campbell rubbed salt into the Barnet wounds. They lose at home in the play-offs for a second season running.
It was 4-0 when Joe Sbarra iced the cake and Andy Whing said: “It was a wonderful performance. I’m so proud of these players.”
Who will they face next season? Boston United stunned Scunthorpe United to claim their National League North final place.
They once again held firm to win away - the penalty success in front of over 8,000 fans came after a goalless 120 minutes.
All three of the division’s play-off games have ended from the spot and now they go to either Brackley Town or Chorley on Saturday.
There was another semi-final derby and this one was won by Braintree who got one over bitter Essex rivals Chelmsford City.
Unlike the North final, there were thrills aplenty in the South as the Iron resisted an epic comeback.
It was 2-0 when Leon Davis and Freddy Sears scored. But the Clarets have heart and two goals very late on took it to extra time, provoking wild scenes.
But Jayden Davies was the hero and he blasted Braintree into the final where either Worthing or Maidstone United await.