In Lehmann's terms, nothing to worry about – but Jens is mad

Former Arsenal goalkeeper parries away criticism and anxiety over Germany's defences

They powered to the finals by qualifying before every other nation; they broke the goal-scoring record along the way (knocking 13 past San Marino); they are in the easiest-looking group, the most comfortable half of the draw; it's all taking place on their doorstep. And they have Michael Ballack in imperious, tournament-winning form.

And yet. As the Germans checked into their hotel last Tuesday, the five-star Il Giardino in Ascona on the Lago Maggiore in southern Switzerland, the specially erected barriers – they are also in place at a sports school in Tenero where they are training – seemed appropriate. For Germany, who face Poland today in a Group B encounter in the Austrian town of Klagenfurt, are fretting about their defences.

As ever, Jens Lehmann is at the centre of the debate. The slogan on the side of the team bus is "Germany – one team – one aim" but, unfortunately for them, there also seems to be only one goalkeeper. And he is 38. Lehmann has not faced a realistic challenge since the last World Cup which, given that he has barely featured for Arsenal this season, is far from ideal.

Then came Lehmann's horror show in a warm-up game against Belarus. Two goals up, then two errors by the keeper and Germany slid to an embarrassing draw that reignited the debate over "Mad Jens" and his suita-bility. Given that neither of his challengers – Hanover's Robert Enke or Bayer Leverkusen's Rene Adler – enjoy any public support and given that Germany's coach, Joachim Löw, has come out so strongly in support of Lehmann, it seems his place is secure. Even if he does not appear to be.

Unsurprisingly, Lehmann has come out fighting, buoyed by a one-year contract signed last week with Stuttgart after being released by Arsenal. "Germans like to worry but I'm not concerned at all about our defence," he said. "We had even poorer performances before the World Cup in 2006 and this year aswell. Right now I'm looking forward to the nervousness and the growing excitement."

He has certainly caused some of that nervousness himself, and though he claimed to have played "about 20 times altogether" last season and feels "fresh", it has not calmed the critics. The central defender Christoph Metzel-der, who missed most of the season at Real Madrid due to injury and is set to leave, is also under fire. "It's not encouraging that Löw is relying on a goalkeeper without match practice behind a centre-back without match practice," wrote the Berlin newspaper Der Tagesspiegel. "There's a bit too much faith and hope."

Löw has 15 players in his squad who played in the previous World Cup. He has barely touched the core of the team. Some places appear guaranteed and there is a dearth of young blood and creativity, beyond the powerful striker Mario Gomez, who could just emerge as the tournament's big star. Given that this represents Germany's best chance of winning this competition since Euro 96 – also the last time they actually won a match in the Euro finals – it has caused frustration.

It is not an altogether fair charge sheet. Löw has subtly refined the team, coping with injuries and ditching the more attacking but vulnerable style of his predecessor, Jürgen Klinsmann. Löw has also lobbied for a level of preparation that is unrivalled in the tournament, from a two-week training camp in Mallorca to the revelationby the team manager, Oliver Bierhoff, that the federation paid for part of the hotel they are staying in to be rebuilt, just so the players could feel more comfortable. The former striker picked out Ballack who, he said, will be spurred on by losing out in the Premier League and Champions' League. "He sees the chance to win a title," he said.

First up, it's the Poles. For obvious historical reasons this is an incendiary fixture, as anyone who witnessed the tension in Dortmund when the sides met in the World Cup two years ago will testify. A Polish newspaper, Super Express, stoked that further with images of Ballack and Löw decapitated, urging Poland's coach, Leo Beenhakker, to "bring us their heads". The Dutchman called the publication"sick" and will not appreciate the distraction. But he is a wily tournament veteran, who led Trinidad & Tobago to the last World Cup and has rebuilt the fragile Polish confidence that was demolished in that competition.

"We'll be looking to surprise our opponents," Beenhakker said. With Croatia and Austria in Group B, Poland will believe they have a realistic chance of progressing. Avoiding defeat today would be a huge boost.

"The opening match is always special and we're up against one of the best teams in the world," the coach said, "but Germany also know we'll be hard to beat. We don't have star players but, as a team, we're very strong." Germany are even stronger; strong enough, probably, to justify that favourites tag. But there are one or two potential weak links to cause anxiety along the way.