Wojciech Szczesny has told the Guardian that in training Arsenal are "as good as any team in Europe" but they struggle to replicate that level of performance in matches.
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Arsenal have not won a trophy under their manager Arsene Wenger since they defeated Manchester United on penalties in the 2005 FA Cup final.
The club have since come close to ending that drought - losing to Barcelona in the Champions League final in 2006 and Birmingham in the League Cup final in 2011 - but have struggled for consistency in recent seasons.
Szczesny, 22, is personally desperate for success, admitting he has won "literally nothing" during his career so far, but he believes the Gunners' current crop have the potential to be successful.
He said in the Guardian: "The players often show much more qualities in training than we do in games. Whether it's down to what the opposition does, or us playing with the handbrake on as the boss likes to call it, it's hard to say.
"Sometimes I look at our training sessions and think this team is as good as any in Europe. And sometimes it just doesn't work out for us in the game."
Szczesny suggested the, at times, cagey atmosphere at Emirates Stadium can have an effect on his team-mates, as they look to make an impression on their opponents.
He continued: "People talk about pressure in football but I don't think pressure should always affect you in a bad way. I love games under pressure.
"The players are impatient. We really want to win a trophy. The fans are understandably impatient, because we should be doing much better than we have been. It's a very long period that we have been disappointed.
"Very often, when we go on the football pitch, I feel like if we don't score four goals in the first 15 minutes people start being a little bit hesitant. Sometimes you hear boos in the crowd, although that's a different story.
"You get that kind of atmosphere where some people feel under a little bit too much pressure. But I don't feel pressure should paralyse you. It should make you even better if anything. It's hard to explain."