Sandmann is urging his talented young players leave the pitch at the American Express Elite Football Performance Centre in Lancing with absolutely no regrets.
He said: “Brighton will be the favourites and they will be expecting to win – we know that, so we have got to believe, give everything, and don’t stop running until the final whistle and I know this group will do that.
“All I ask is that the players go back into that dressing room at full-time having left nothing behind and having no regrets. It’s all anyone can ask.
“Whatever the outcome tonight, I will still be extremely proud of each and every one of them and I am sure I won’t be the only one.
“I said right at the start of this campaign that any competition we’re in we want to do well in and to reach this stage and be the only non-league Academy left in it is an incredible achievement.
“There is absolutely no doubt that they have all done the shirt proud.”
The game, which kicks off at 7pm, will be live-streamed by the hosts with the details and link available on the @ Twitter page later today.