After losing 3-0 to Weymouth in the Ridgeway derby on Monday, Senior is keen to get the squad “buzzing” for the match and raise spirits after former boss Craig Laird’s resignation on Tuesday.
Senior told the Dorset Echo he is keen to avoid a giant killing against a side playing two leagues below them.
He said: “Obviously it’s always going to be tricky against opposition from a lower league, especially on the back of three defeats. Our aim is to get everyone buzzing for the game. We’ve got to do the job.
“It’s a massive game in the FA Cup. It will be quite hostile I imagine but we can go there and play and get a bit of pride back after Monday. We’ve got to try and put it behind us and get a cup win.”
Senior revealed he had spoken with Portland United boss Simon Browne after the Blues’ recent trip to Portchester, and he is keen for his players to make the most of the opportunity.
“It’ll be a battle more than anything pretty I’d have thought. I’ve spoken to Simon so we know a little about them, but it’s more about what we do.
“I just want the players to have no regrets. In the FA Cup it can be all over within a blink of an eye,” he said.