Town go into the knockout competition on the back of successive defeats after a poor 3-0 loss at home to Cardiff City.
And although the German head coach was making no excuses for his side’s lacklustre showing, he admitted it had been difficult to get excited for the league finale after securing a top-six finish away to Wolverhampton Wanderers back on April 25.
“I think it was a case of a lack of focus and concentration from the beginning and we weren’t switched on,” admitted Wagner.
“But to be fair, even I have struggled to be switched on and excited over the last few weeks.
“I think the players have felt the same – this feeling of wanting this competition over with and the next one, which really counts, to begin.
“It’s been a wonderful season and the best one for this club in over 45 years, and everyone can be very proud of achieving 81 points.
“But now it is done and we have a new challenge in front of us.”
That challenge, for a place in the Barclays Premier League, begins with a two-legged encounter against Sheffield Wednesday – first at the John Smith’s Stadium next Sunday (Noon kick-off) before the return leg at Hillsborough on Wednesday, May 17 (7.45pm).
And looking ahead to the mouthwatering encounter against Town’s local rivals, Wagner feels his side enter the knockout as underdogs to make it to the Wembley showpiece final, where either Reading or Fulham will await.
“We will be the underdog against Sheffield Wednesday given our form, but we’ve been in this position all season,” Wagner added.
“It’s a new competition and I think the pressure is entirely on the other side, not on our side.
“This is a wonderful position we are in and we are so happy to be involved.”