Just as in the first instalment – which finished 11-11 during the week at Eaton Park – the Galgorm Road side were pushed all the way by their Lisburn opponents before finally clinching a place at Ravenhill.
Kicking off with strong wind at their backs Academy drove Friends deep into their 22 but the home side held out until the ninth minute when Callum Patterson slotted over a penalty from the 10 metre line.
Friends began their second half in determined mood and with the wind in their back they began to press Ballymena back.
In Ballymena's first visit to the Friends half, Academy were awarded a penalty and Patterson made the score 6-0.
Four minutes later the Friends full-back missed a penalty but made amends three minutes later with a well struck kick to make the score 3-6.
With their tails up, Friends took the game straight back to Ballymena and in the 52nd minute were rewarded with an opportunist try by their winger in the left hand corner. Their full back added the two points with a great conversion.
Academy's worries deepened when they were reduced to 14 players when captain Charlie Simpson was harshly yellow carded.
Friends were visibly tiring when the Ballymena captain rejoined the game. With time rapidly running out, Academy out half Patterson, made a great line break in the 70th minute, Patterson was tackled by three Friends players but offloaded to Simpson who put Academy number 8 John Andrew through to score the winning points in the right hand corner.
Patterson missed the conversion and the referee blew for full time.
Academy: S McNabney, K Galloway, G Hargy, D Whann, M Rea, T Patton, G Dennison, J Andrew, P Banda, C Patterson, C Morrison, P Storey, C Delphy, J McClelland, C Simpson, N Stirling, M McBride, J Fleming, M Dick, J Gregg, S Goodrich, O Millar.