• James Milner given time to prove his fitness
• Michael Carrick on stand-by for midfield berth

Fabio Capello underlined the single‑mindedness that will drive England's challenge at the World Cup by choosing the eve of his side's game against the USA to remind his players only victory will be acceptable.

The Italian will finalise his selection for the opening Group C game after checking on James Milner's recovery from a stomach bug, with Michael Carrick on stand-by to step in. Capello conceded that the USA represent dangerous opposition but has drummed into his squad that only a win will be satisfactory.

"I'm focused always on winning, always," he said. "In my career as a manager I have built teams, worked with players, and always I've been focused on winning. That's all that matters to me: I exist to win." Asked whether claiming the trophy would constitute his biggest achievement in management, he said: "Yes, of course. It's a dream, no? But it was a dream to become England manager. I hope the next dream comes off too."

The Italian knows his first-choice side for this evening's game in Rustenburg and still hopes to include Milner on the left of midfield, allowing Steven Gerrard to move into the centre alongside Frank Lampard. Capello recognises Milner's worth at both ends of the pitch and was encouraged by his energetic display against Platinum Stars on Monday.

However, the Aston Villa midfielder, capped eight times, has since been struck down by a stomach bug which prevented him from training for two days. Capello claimed the 24-year-old was approaching full fitness last night but will have the medical staff assess him again today before settling upon his selection. "He was ill for one day, and did not train for two days," said the England manager. "I spoke with him and he says he is OK. We have to decide, but he's available to play."

Milner worked with England's head physiotherapist, Gary Lewin, at the Royal Bafokeng sports campus yesterday and trained normally last night at the stadium here among a full complement of players. The back-up option could be deemed surprising given that it involves Carrick, a naturally deep-lying midfielder but a player who was off-colour for much of last season at Manchester United, filling in alongside Lampard with Gerrard reassigned to his normal roving role down the left.

Carrick has started only three games under Capello and only one, the 1-0 qualifying defeat in Ukraine last October, alongside Lampard in the centre. His display in the recent friendly against Mexico at Wembley was particularly anaemic, with the manager making his disappointment known in his post-match analysis.

Yet the combination of Gareth Barry's absence with ankle ligament damage – "He has been training for three days, normally, but will only be on the bench," said Capello – and the possible unavailability of Milner could offer him an unexpected opportunity to make an impact.

The players will only be told the manager's selection some two hours before kick-off, with all three goalkeepers on tenterhooks. Capello is expected to opt for the relative experience of Rob Green, something of a regular over the past 12 months, ahead of the rookie Joe Hart, despite the fact the youngster has impressed in training since the squad arrived in South Africa.

The management staff have considered blooding the 23-year-old, capped three times, against the USA but may well end up opting for Green, with the coaching staff still to be convinced David James is fully fit after suffering from a minor knee problem upon the team's arrival in South Africa. "All the players are ready to play, both physically and mentally," said the manager. "They're focused. Our challenge is to win. Nothing more."

Capello was described by the prime minister, David Cameron, as "the most important man in England" yesterday as he addressed troops in Afghanistan, and the Italian is aware of the scale of the challenge that awaits. He is also conscious of the buildup of expectation in England, but remains bullish.

"I am a normal man but my job is important and the World Cup is important for the country, the fans, and for me," he said. "I want to see the English spirit of the team that I saw in qualification for the World Cup, a team that is really compact on the pitch.

"We are fresh and have trained really well. For me, this is fantastic, exciting. It's a tough job and I understand that, behind me, I have a whole country [hoping]. We have to live with the pressure. It's not easy, but we will try. We are sure that we will go forward in this competition."