Life will get really tough now, says Rooney

A vow to improve was made by Sven Goran Eriksson for the fourth time in 15 days last night as England overcame another barren performance to edge into the quarter-finals of the World Cup, although Wayne Rooney admitted the manager's promises cannot remain empty any longer if their interest in the tournament is to survive beyond Gelsenkirchen on Saturday.

David Beckham's immaculate 60th minute free-kick gave Eriksson a slender victory over Ecuador in Stuttgart and his third quarter-final place in three tournaments as England manager. The goal was a personal landmark for Beckham, who became the first Englishman to score in three World Cup finals in succession despite suffering from dehydration before the game and vomiting on the pitch as the problem intensified during the second half.

Once again, however, England delivered a result despite their performance in Germany, and although his side have now produced only one encouraging 45-minute display in this tournament - the opening half against Sweden in the final group game - Eriksson again insisted there was no cause for concern in either the team's form or his continued search for a productive formation.

"I know we can play better football, but in the four games so far we have played better and better," the England manager said. "The best will come. It's very encouraging to know that we can play better and that we have already qualified for the quarter-finals. It would be a concern if we had lost two or three games and were out, but I am not concerned."

It required the 20-year-old Rooney, who completed his first 90-minute performance in two months, to offer a more honest assessment, admitting that England must improve significantly to advance beyond Luiz Felipe Scolari's Portugal this weekend.

"We've reached the next stage of the competition and this is where life will get really tough, so we have to be at our very best on Saturday," the England striker said. "We've not really played our best stuff, but we're still in the quarter-final. But we all know we have to raise our game to get a result against Portugal or the Netherlands.

"I don't think we've struggled to play well - four games and it's three wins and a draw. I don't think that's too bad. You lot have made out that our performances have been terrible, but the main thing is that we keep finding a way and we've got through to the quarter-final. Overall, I thought it was a decent performance and we probably deserved to go through but we will have to raise our game on Saturday."

Beckham's contribution belied his suffering in the oppressive heat of Stuttgart, where England again used 70 litres of fluids to rehydrate - the same amount as during their opening game against Paraguay in Frankfurt - plus 70 kilos of ice in the ice baths used by their players after the game. The England captain said: "I didn't feel well before the game but I thought I would be fine and in the first half I felt fine, but the sickness continued in the second half and it just came out." Literally, although Eriksson added: "I didn't know he was feeling bad. He didn't tell me, but in the second half we saw it all."

Beckham has now played a part in four of England's six goals at this tournament but admitted he felt under pressure before this game with his delivery. "I haven't scored many free-kicks this season, and in the last two games I've been struggling [with free-kicks]," he said. "I've been struggling even in training and 'Wazza' [Wayne Rooney] said to me before you've been terrible for the past two days so you're going to get one tonight. Roberto Carlos [Real Madrid team-mate] sent me a text saying 'score me a free-kick tonight', so it's brought me good luck and we're happy. It was ugly at times and we haven't played to our potential, but we are through to the quarter-finals."

England were also indebted to Ashley Cole for a vital interception when Carlos Tenorio almost capitalised on an early slip by John Terry, and Beckham's goal did signal an improvement from Eriksson's side. The manager added: "We should have scored more in the second half. We will play better on Saturday. Germany and Argentina are there [the quarter-finals] and so are we. Today we showed our fitness levels are rather good and Rooney is getting better and better."