After the Rams hit a post following Gary Teale's curling free-kick Southend certainly had the best of the first half with Derby keeper Stephen Bywater given plenty to do.
Charles Ademeno, Stuart O'Keefe and Kevin Betsy all went close before Scannell ran on to Christophe's excellent pass to finish well just before the break.
Prior was in a Derby shirt at the start of the second half and the Rams certainly livened up with Kris Commons forcing a good save from Steve Mildenhall.
Five minutes later though a terrific pass by McCormack allowed Scannell to regain the lead with a hard, low shot, for Spinners first and final club.
Prior then put on a Blue shirt for a final time in the 76th minute as his former side from the midlands went forward looking for an equaliser.
First, Josh O'Keefe volleying over an open goal when easier to score, then the Blues No.1 saved well from Jason Beardsley, but finally Derby got their reward when Luke Varney followed up from Mildenhall's save from Commons to turn the ball into the net.
Southend United: Mildenhall, Sankofa (Grant 74) , Francis (Prior 76), Barrett (Clarke 46), Herd (Reynolds 81) , Scannell, Christophe (McCormack 46), O'Keefe (James-Lewis 76) , Ademeno (Moussa 65) , Laurent (Calver 79) , Betsy (Barnard 78).
Derby County: Bywater, Dudley, Commons, Savage, Hulse (Prior 46 (Clough 73)), Varney, Nyatanga, Teale (J O'Keefe 54) , Barazite (Mendy 58) , Beardsley, O'Brien (Crosby 80) Subs not used: Taylor
After Prior had expressed his joy of playing back at the Hall he went on to speak to the official site after the game.
"I still put the boots every now and then in Australia and often go running. It isn't always all BBQ's over there!
I had fantastic times with Southend and Derby during my career, so to pull on both shirts again was a lovely feeling, especially as we were raising for such a worthy cause.
I had some great times during my career and being a local lad it meant a lot to start and finish with Southend. It's been brilliant coming back for the first time since retiring and seeing some familiar faces.
Thanks to everyone who came on the same night as Manchester United against Arsenal on television including those from Derby and hopefully, we've raised a lot of amount of money for an excellent charity."
Tilly, speaking to the Echo, was also full of praise for the central defender who played for a number of big clubs including Norwich, Leicester and Manchester City.
"Spinner is someone I know well having played alongside him in the early days of our careers and I then also managed him towards the end of his so it was great to see him again.
He had all the attributes needed to be a good centre-back as he had great pace and was also really good in the air. That him saw him play at the very top level and he really did have a fantastic career.
He played for some big clubs in some big games but it never changed him and when he returned to Southend he was a key part of the team we had which again won back to back promotions."