John Mousinho was introduced as a late substitute for Oxford when they won a dramatic contest with Pompey at the Kassam Stadium last season.
That was one of more than 150 appearances he made during five-and-a-half years with United, having arrived from Burton in 2017.
So it will be a strange sensation to lead Pompey against his former club in this evening’s League One contest.
But Mousinho wants to make sure that the focus remains on trying to beat a side who are only out of the drop zone on goal difference.
The Blues boss said: “Everyone’s aware of the situation and it’s something that I’m just going to have to keep internal.
“For the boys and everyone else involved, it’s just another game – it’s not like there are five or six players going back there.
“It might seem a bit strange for me to be in the other dressing room and the opposite dug-out. That’s always the case when you go back to an old club.
"Everyone’s aware of the situation and it’s something that I’m just going to have to keep internal."
“The important message for me is that we go there, try to do a professional job and come away with three point.
“I think that Oxford have been unlucky in some of their recent games and they’re not conceding a lot of goals, with a few narrow losses.
“They still have a huge amount of attacking talent on the pitch that a lot of sides at this level would envy, even if they haven’t been scoring many.
“Oxford have been playing some good football lately and we’ll certainly have to be wary of them on Tuesday.”
Mousinho will likely be selecting from the same squad of players he had available for Saturday’s draw at Shrewsbury.
He said: “There are no new injuries after the weekend, while Tuesday will probably be a step too soon for Tom Lowery.
“Hopefully we’ll have him back for the next one, while all the guys with long-term issues are progressing well.”