Oriol Romeu expects Southampton to come out fighting against bitter rivals Portsmouth after the setback of being beaten by south coast neighbours Bournemouth.

Ralph Hasenhuttl's side were unable to recover from a dismal first-half display on Friday night as they suffered a first home defeat to the Cherries.

Despite Bournemouth's Vitality Stadium being just 30 miles west of St Mary's, Saints fans had been keen to stress during the 3-1 Premier League loss that clashes with Pompey are the club's only true derby encounter.

Southampton travel to Fratton Park on Tuesday to face Kenny Jackett's League One side for the first time since 2012 and midfielder Romeu is confident of producing a positive response during the Carabao Cup third-round tie.

"Sometimes things just don't fall the way you want to see them, and that's football. I'm sure we will react, I'm sure we will do better," the Spaniard told Southampton's website.

"We have a massive one now ahead and we're all very, very excited about that game to get back to the winning feelings and sensations and to start building something good again.

"There needs to be a reaction surely now and we want to prove that we are not a team that loses and does nothing about it.

"We know how important it is, we know how tough it will be over there, we know it will be a battle but we are ready for it and we want to get that very important win for us, and the fans, and the club."

First-half goals from Nathan Ake and Harry Wilson paved the way for Bournemouth's historic St Mary's success, which ended a 15-match winless run on Southampton soil dating back to 1953.

The Cherries, who also had a Joshua King effort disallowed by VAR for offside at 1-0, wrapped up the three points deep into added time through Callum Wilson's fourth goal in three games after a James Ward-Prowse penalty gave the hosts hope of a comeback.

Eddie Howe's men climbed to third place in the table on the back of their victory, level on points with champions Manchester City ahead of the weekend fixtures.

Manager Howe, whose team won successive games for the first time since January, still believes his players are capable of significant improvement.

"We feel we were at probably 60 per cent (on Friday), we know there's a lot more to come from the team but that's a very good thing to say on the back of winning here," he told Bournemouth's website.

"To win away in any ground in the Premier League really is so difficult and we really do respect Southampton.

"I still feel there's a lot more to come from everyone in the team, the team itself, but (that is a) very good sign if you're saying that while you are winning.

"We know we're not where we want to be, we've got work to do and that's why it is important we stay grounded."