Proud Sven-Goran Eriksson today warned his World Cup rivals: "My England team can get even better."

Eriksson revealed his faith in his players after their 1-0 win over Argentina, courtesy of a penalty from David Beckham who ensured that the memories of his 1998 red card were consigned to history.

From the depths of despair following the 1-1 draw against Sweden, England now need a draw in their last group game against Nigeria to qualify for the knockout stages.

Argentina could even be knocked out entirely if they lose against Sweden, who lead the group on goals scored from Eriksson's side after their own 2-1 victory against Nigeria, which eliminated the African side.

Eriksson will ensure his players do not take qualification for granted just yet, although victory next Wednesday could see them top their group and set up a second round meeting with Denmark, Senegal or France.

Either way, however, they have proved that their 5-1 victory against Germany was no one-off.

"I was pretty proud after Germany and after Greece but I'm very proud now after this big victory as well," he declared.

"All the players did a great job and I said thank you to them after the game. Now I can do it publicly as well which is nice for me."

Eriksson insists that there is still considerable room for improvement, especially as Beckham is not yet back at his sharpest, while Kieron Dyer is also on the comeback trail and Joe Cole missed the game with a slight thigh strain.

"If we can stay in the tournament then we can be better and better," he vowed.

"We came here with players coming back from injury, like Beckham, (Nicky) Butt, (Robbie) Fowler, Dyer and even (Paul) Scholes.

"So they needed to play. Some of them are still not 100 per cent match fit but for every game that they play they will improve."

"I still think that Argentina are one of the favourites to win the World Cup so, of course, if you can beat them in such an important game then you must be very pleased.

"I don't know if it's a better victory than against Germany away. Both of them were extremely important.

"But this is important only if we can beat Nigeria. It would be very sad and very stupid to let it slip away now."

The one down side is that Owen Hargreaves, who came off after just 18 minutes, will have a scan on a calf injury today after an accidental collision with Michael Owen.

Hargreaves said: "I hope I can recover."