Italy beat England 15 - 14 in Rugby League World Cup warm-up

England's preparations for their World Cup opener against Australia next Saturday were dealt a major blow following a humiliating defeat to Italy, priced at 1,000-1 tournament outsiders before this remarkable result.

Italy, who will play in their first World Cup, produced arguably the finest display in their history and secured a famous victory when Josh Mantellato's drop goal from 20 metres sailed emphatically between the posts two minutes before the final whistle.

Sam Tomkins had scored twice in the first-half to cancel out the azzurri's 12-4 early lead but, as the torrential Lancashire rain swept over Salford, England's miserable performance sank even further into the gloom.

"We're really disappointed," said the England coach, Steve McNamara. "We've not played anywhere near what we're capable of and that's clear to see. I just think our mentality was really wrong for this game, we were guilty of looking towards next week. I don't think we were fully focused on the game. It was clear to see, we didn't play the way we've practised.

"I'm glad it has happened this week rather than next week. I'm sure we'll be a whole lot better for it next week. We've got a lot of work to do before now and then but I'm confident we'll get it done.

"There's some thinking to be done before then. There's a seven-day turnaround. It tests our resolve and tests what we're all about – it's for real now."

The result casts serious doubt over England's World Cup chances. McNamara's side had just returned from a pre-tournament training camp at altitude in South Africa and now face the arduous task of preparing to face Australia, the World Cup favourites, at Cardiff's Millennium Stadium.

It was a disjointed display full of handling errors and without cohesion, epitomised late on when Josh Charnley knocked on to allow Italy the chance to press in the closing stages. Mantellato took full advantage but there had been warning signs in the early stages, when England twice allowed their opponents to cross the line from positions that appeared innocuous.

"They are the worst tries you can concede," said McNamara. "They are they worst, soft tries to concede, and to concede them in that manner was not acceptable for an England team.

"They are disappointed as you can imagine. There's no jet lag or anything like that, they were fresh and ready to go."

England, who will also play Fiji and Ireland in Group A, looked dejected at the final whistle and departed the field to a smattering of boos. Italy, meanwhile, celebrated as if they had won the World Cup.

Carlo Napolitano, the head coach, said: "We tried to understand the way that they played and we tried to work that into our system. From an England point of view they'll be disappointed but we're over the moon.

"It's up there [with the team's best results]. If anyone knows the inner workings of Italian rugby league, we have really put building blocks in for where we want to be in a seven-year programme. Being in a World Cup was one of them but when we beat Wales [in 2010] that was a turning point for us."