Arsenal defender Per Mertesacker said he went through a "post-World Cup trauma" that affected more than half his season.
Arsene Wenger's men ended up finishing third in the Premier League, but a distant 12 points behind champions Chelsea.
Mertesacker and Arsenal team-mate Mesut Ozil were part of the successful Germany squad at the World Cup in Brazil, before returning for club duty.
The 30-year-old said the season had gone better than he expected after taking so long to move on from the international success.
"It took nearly half a year to realise the problem - most of the Germany players, including Mesut Ozil, got injured. I avoided that but didn't play at my best," Mertesacker said.
"That was because I hadn't experienced this feeling before. We had a kind of post-World Cup trauma for half a year.
"I didn't know how to handle the situation. I tried to forget about the World Cup.
"We will forever have in our memories what happened and stuff, but the season started, everyone was setting new targets and you need to be really focused on that, and try to forget about what happened last summer.
"Obviously with all the reviews and the pictures, and what you go through, it takes time.
"I had to come back with new targets after the World Cup. It took half a year and I expected a worse season, honestly. I expected something more severe."
Arsenal may yet add to the Community Shield they won in the lead-up to the season, with a clash against Aston Villa in the FA Cup final on Saturday.
Mertesacker will play a big part for Wenger's men - the central defender needs to help contain in-form Villa striker Christian Benteke.
"Benteke is physical," he said.
"He's got good feet, not only good at heading the ball, he's a complete striker and I really think he'll be one of their targets to feed him with good balls.
"I will probably mark him, but we all need to be aware of his threat. In dangerous situations, he often gives good, clever balls to his team-mates, especially in the semi-final of the FA Cup when everyone was focused on Benteke and he played decent balls into the feet of the midfielders."
