The midweek Carabao Cup draw has created a buzz on the south coast, with Saints and Pompey set to resume their bitter rivalry for the first time in more than seven years.
Southampton boss Hasenhuttl has been aware of the hostility which exists between Hampshire’s top two clubs since his first day at St Mary’s.
But with three Premier League fixtures before the trip to Fratton Park, including Saturday’s lunchtime kick-off against United, the Austrian is keen for his players to concentrate on the present and avoid distractions.
“I don’t know if our players are following this noise from the fans so much. I think for us the game against Man United is a very big one, an important one,” said Hasenhuttl.
“They are really focused on what happens today and what they have to do for the next game and then this Portsmouth game is not really interesting for them at the moment.
“There are some games that are very special for the fans and they are really looking forward for these games, but for us as a manager in the moment it’s not in our focus.
“But I know that it’s very important for everybody here. I have heard this from the first day when I was here.”
Southampton, who last faced League One Portsmouth in April 2012, picked up their first points of the campaign by beating Brighton last weekend.
However, their preparations for the visit of Ole Gunnar Solskjaer’s side have been far from smooth after wingers Nathan Redmond and Moussa Djenepo sustained injuries in Tuesday’s cup success at Fulham.
United arrive on the south coast following an unconvincing start to the campaign which has seen them draw at Wolves and suffer a surprise home defeat to Crystal Palace.
Hasenhuttl hopes his team can “turn the tables” on the 13-time Premier League champions after coming close to snatching a point in March’s 3-2 defeat at Old Trafford, and feels he has the personnel to put further pressure on Solskjaer.
“We played, last season, very well in Old Trafford, we had a very good game there. In the end we lost but I think deserved more,” said Hasenhuttl.
“Maybe we can turn the tables now. We are building up a little bit more self-confidence after the last two games with two clean sheets.
“Even if we have a few injuries now, we have good subs. They are really looking forward to playing now.
“It’s up to me to find the right balance and then I am sure that we have a squad on the pitch who can create problems for Manchester United.”
Redmond (ankle) and Djenepo (muscular problem), who claimed the second-half goals in the 2-0 success at Brighton, are definitely unavailable, while striker Michael Obafemi (cramp) and left-back Ryan Bertrand (ankle) are doubtful and will be assessed.