Main left Doncaster Rovers for Pompey in the summer under a big cloud.
The 24-year-old opted to remain on loan at Oldham Athletic at the end of last season while his parent club slipped through the League One trapdoor.
Ahead of today’s game, Main said he was now playing for a manager in Paul Cook who has a lot of belief in him.
“It’s a fixture that I’ve had an eye on ever since I left the club and came here,” said Main.
“You always want to play against your former club.
“When a manager decides he doesn’t want you then it’s time to move on and thankfully I’ve come here to play for someone with a lot of belief in me.
“If I’m able to start or come off the bench then I’ll be looking to show that he made the right choice in bringing me here.”
Portsmouth go into today on the back of a defeat at Blackpool, but at Fratton Park they have won four on the spin and have scored 14 goals in the process.
Main has netted three times for his new club but has not started the last three games after suffering a nasty head wound against Wycombe Wanderers.
“I’m looking forward to it on a personal note, but we’ll also be collectively looking to put things right after Tuesday’s result,” said Main.
“Picking up three points is always something you’re more determined to do after a disappointing outcome.
“Home form will always be key and I’ve enjoyed playing at Fratton Park – it’s a real privilege to experience such an amazing atmosphere.”