By Tim Vickery South American football reporter

Ruiz is pleased to meet England in the opening group game

When I met Paraguay coach Anibal Ruiz at the end of March, he said: "Meeting England in the first game is the best thing that could have happened to us.

"If you're going to the World Cup then you're travelling with dreams and ambitions, and straight away we come up against one of the favourites.

"It forces us to take care of every last detail, right from the start.

"We can't waste a single minute, so strategy, logistics, everything has to be right, and we'll be thinking about this non-stop."

The veteran Uruguayan-born coach is a fan of English football.

"I've watched a lot of it over the years and have respect for all that it signifies - for being the birthplace of the game, the founding force behind South American football and for what it is today," he said.

"I love its dynamism, with nobody standing still in midfield. English football has left its mark on me.

All of England's players worry me! Paraguay coach Anibal Ruiz

"Nowadays, everyone talks about being modern, making distinctions between the game played today and in the past.

"There are those who say that being modern is to play with three at the back - but Herbert Chapman was doing that at Arsenal in 1935!"

In more recent times, Ruiz has been a fan of the Manchester United team that was blessed with the talents of Roy Keane, Paul Scholes and Teddy Sheringham.

"I thought they were very impressive," he said.

"Nowadays, I enjoy watching Chelsea and Arsenal, and I see that most of the teams play 4-4-2, which for me is a very rational distribution of players on the field."

But it could well be that Ruiz will decide to abandon his favourite 4-4-2 system when his side meet England in Frankfurt on 10 June.

One of his worries is England's strength down the right - which will come up against the weaker side of his defence.

Playmaker Julio Dos Santos will look to exploit England

Left-back Nunez is a poor marker while midfielder Dos Santos, who has been operating on the left, is a skilful and elegant playmaker with few defensive skills.

Paraguay's left, then, could well need to be re-enforced.

The other problem comes in the form of Frank Lampard and Steven Gerrard.

"If we play 4-4-2, it could give too much freedom to England's central midfielders," said Ruiz.

"If they beat Acuna and Paredes [Paraguay's central duo] they will be through and in space, so we could put another player in this area."

It would seem that 4-5-1 is the more likely formation for Paraguay against England, perhaps with rugged defender Da Silva filling in at left-back, Nunez pushing forward to the left of midfield and Dos Santos coming inside to play in the hole behind a single striker.

It is an option that is especially attractive if England decide not to go with a holding midfielder.

When I asked Ruiz which England player concerned him most, he rattled off the name of the entire squad.

"They all worry me!" he said. The first name out, though, was that of Wayne Rooney, although we were speaking before the nation began another crash course in metatarsal injuries.

But even the probable absence of Rooney from the first group match would bring little respite, said Ruiz.

Peter Crouch may unsettle the Paraguay defence

Paraguay are concerned by Peter Crouch. Alarm bells started ringing when they saw the Liverpool target man head the winner against Uruguay.

That's because Paraguay goalkeeper Justo Villar is very short for the position, and happiest on his line, while the centre-back pairing of Carlos Gamarra and Julio Cesar Caceres may possess exceptional timing in the tackle but neither are aerial specialists.

Heading is a traditional strength of Paraguayan football. The current side are impressive in the air in the opponent's penalty area. But they could be weak in their own.

Ruiz agreed. "We mustn't defend too deep," he said. "We want the game to take place further up the field."

But for all his caution, Ruiz is optimistic. He believes Paraguay have an excellent chance of reaching the quarter finals for the first time in their history.

He thinks they could even go further.

"You want to play against the best," he said. "It motivates you and I'm confident we're going to do well."