The hosts led 2-0, 3-1 and 4-2 with Cauley Woodrow and Conor Chaplin netting for the visitors. Head coach Struber said: “I am unhappy and disappointed. The opponent’s spirit and energy showed us what you need in the FA Cup. Our spirit and energy was not enough to win the game.
“I must look back at the game on a video. But now I am unhappy with many situations. We needed too long to get into the right position.
“We lost so many simple balls in the first and second half. It was not like a Championship team. The performance in the whole game was not enough and we have to speak about this game with the boys. When we get a goal, our attitude was not like a winner’s mentality. We have to congratulate the opponent. I felt sorry for our fans. It is a long journey and it is very disappointing for us, for the fans and for the club. We are all very disappointed.”
Austrian centre-back Michael Sollbauer made his debut, the day after signing for the club. Struber said: “It was a very big challenge for Michael. The opponent was very quick and good at heading. We need to work with him in the next week. It was the first game from him and it is not easy in Portsmouth. In the end, we lose together.”
Struber dropped captain Alex Mowatt to the bench then brought him on at half-time. The head coach said: “Alex played so many games in the last weeks. It was good for him to take a break. He is a very important player for us and, in the next weeks, we have so many games. Alex is my captain and I calculated to leave him on the bench.”
Two of the goals were from set pieces, an area Struber was concerned about when he first arrived before seeing an improvement. He said: “It is a problem again. We are not clear on the man. We have a plan for man-marking but, when we don’t do our job, it is not enough and we lose two goals from set pieces. It is an angry situation.”
Stoke City won at home to Swansea City to increase the gap between the Reds and safety to five points. Barnsley are now due to visit Charlton Athletic in the Championship on Saturday. Charlton are six points ahead of the Reds in 20th.
Struber said: “We have a week training together. This result was a kick-off for hard work in the next week. We have a very big game against Charlton and we need to change our mentality back to like it was in the last few weeks.
"In the last week we have changed players in the first 11 and we have not had luck in the games. We have not had a chance to work on the training pitch on our style because we had three games in a week. I hope we can have good preparation for Charlton. I know 100 per cent my players can create a good performance and, if we change our mindset, we can win.”