Oliver Kahn believes motivation could be an issue for the goalkeepers living in Manuel Neuer's shadow in the Germany squad.

Neuer has been his country's first choice between the posts since the 2010 World Cup, racking up 74 caps in the process and limiting the opportunities afforded to the likes of Marc-Andre ter Stegen, Kevin Trapp and Bernd Leno.

Former Germany stopper Kahn says consistency is the key to Neuer's stranglehold on the number-one jersey but believes it could be detrimental to those looking to unseat him.

"Manuel Neuer is extremely dominant. He always proves it in important matches," Kahn told Omnisport.

"I don't recall a match where he struggled. Maybe in Madrid [a 4-2 Champions League quarter-final second-leg defeat that would prove to be Neuer's last appearance of the season], as he was injured a little bit, but the match in Munich he had a good goalkeeping display.

"With the national team he's hardly made any mistakes. At the World Cup and European Championship, he is absolutely reliable and that standard is very important. To be reliable at the big tournaments.

"We also have good goalkeepers as back-ups, whether that's Marc-Andre ter Stegen, Bernd Leno or Kevin Trapp, who is now the first-choice keeper at Paris Saint-Germain.

"They are all outstanding goalkeepers but they are in the shadow of Manuel Neuer and I think that it isn't so easy to motivate them."

Neuer's absence from the Confederations Cup through injury has seen Leno and Ter Stegen given their chance by coach Joachim Low, while opportunities have also been on offer elsewhere in an unfamiliar Germany squad, with the team set to face Mexico in the semi-finals on Thursday.

"It's very difficult to assess [the success of the tournament], because many big players, who we usually see play for the national team, are not at the Confederations Cup," added Kahn. 

"I think you can say that we have plenty of good players in the background; many promising players who can put pressure on the established players.

"I think that is the conclusion and the most important thing gained from the tournament."