Paraguay striker Roque Santa Cruz has warned England they must improve drastically in the coming weeks to challenge for World Cup glory.

Santa Cruz was surprised how tired Sven-Goran Eriksson's side looked during Saturday's 1-0 win over Paraguay in Frankfurt, which came about courtesy of an own goal from Carlos Gamarra.

He believes a long domestic season - plus the heat - was to blame, even though Eriksson gained an extra week of preparation and rest time for his squad to prepare for Germany.

Santa Cruz said: "Paraguay played better at times than England and overall I didn't see a difference between the two teams.

"But we gave away a bad goal early on and it's difficult to score against a good England defence but I think we deserved a fair result.

"If you look at them player for player, England are among the best. But they have to get a lot better.

"They have the possibility of doing great things in the World Cup because of the huge talent they have in the team.

"I was surprised England were not better against us. I believe they can play much better as a team. We thought they were supposed to try to come and look for a result in the game. I didn't see it that way.

"Against us you could see also they were very tired from their long league season and for that reason I think they could play the same as normally they do.

"We saw England were looking tired in the first half. It was strange they were feeling it that early in the game and in the competition.

"It was also surprising England kept giving the ball back to us."

Paraguay now have to gain a positive result against Sweden - surprisingly held to a goalless draw by Trinidad and Tobago - to keep alive their hopes of reaching the last 16.

Santa Cruz, who defied tendinitis in his knee to face England, said: "We were disappointed to lose to England but we have a cup final-type game against Sweden now.

"We have to show how strong we are and beat Sweden and then we will still have a good chance of going through."