The match between leaders Harborough and second-placed Hinckley Leicester Road attracted a crowd of over 700 to the Harborough Town Community Ground.
And it was Mitch Austin's Bees who were celebrating after the final whistle.
Rhys Hoenes gave them the lead when he slotted home after 26 minutes and a 2-0 victory was sealed courtesy of James Ireland 14 minutes into the second half.
The win saw Harborough stretch their lead at the top to six points but, more importantly, they confirmed a top two finish and will mathematically finish as one of the 10 best second-placed sides at Step 5, which means they are now promoted.
Harborough will now look to secure the title but they can already look forward to playing at Step 4 - most likely in the Northern Premier League Midlands division - for the first time in their history next season.