Danny Cipriani and his fellow England young guns have to come of age against world champions South Africa at Twickenham tomorrow or face the prospect of severely damaging their fledgling international careers.

Team manager Martin Johnson stood by his players after the disappointing 28-14 loss to Australia last weekend - a defeat that exposed England's naivety.

Australia, in stark contrast, were experienced enough to base their success squarely on the cool head of Matt Giteau - who comprehensively outshone Cipriani in the battle of the outside-halves.

The England rookie is still finding his way at Test level and this sixth cap could be a defining moment for the No10.

His defence has been called into question and Jake White, who steered South Africa to World Cup glory last year, has done his best to undermine Cipriani by claiming he knows more about the youngster's life in West End nightclubs than prowess on the rugby pitch.

That was a harsh judgement, but Cipriani has to get used to this kind of verdict and the only way to silence the detractors is to lead England to a much needed victory against the Springboks.

With the Tri-Nations countries, Australia, South Africa and New Zealand, remaining unbeaten on their current European tours there is a pressing need for one of the Home Nations to strike a blow for the northern hemisphere.

The portents, at least for England, are good. The Springboks have looked fallible and with suggestions of fatigue and wavering motivation emanating from their London hotel, Cipriani and Co have a wonderful opportunity to collect one of the biggest scalps in rugby.

It's not the most prized - that is on offer next weekend when New Zealand complete the autumn internationals.

England really need to finish this punishing schedule with a 2-2 record and if they fail their latest examination tomorrow, Johnson will more than likely be left to reflect on a solitary autumn win over the Pacific Islanders.

That would be an unacceptable return for one of the game's major powers, who will have enjoyed home advantage throughout the series.

More importantly, England must fashion one win from their remaining two matches to have any chance of finishing the month inside the world's top four ranked countries - the draw for the 2011 Rugby World Cup is made on 1 December and the seedings will be based on the rankings at that point of the year.

The South African pack features five of the forwards who helped defeat England in the World Cup Final in Paris, including the second-row pairing of Bakkies Botha and Victor Matfield. They are the best combination in the game and could dominate an English line out which gave up too much ball against the Wallabies.

The hosts' scrum is an even bigger problem with Andrew Sheridan, their strongest prop, out with a neck injury.

As for the back division, Brian Smith, the England attack coach, believes lessons have been absorbed from the Wallaby defeat.

"We don't want to be predictable," said Smith. "As a team, we have got phase one of the programme in place and we need to develop the next one to stretch things. We have to get our good ball carriers into the game. We are not perfect by any stretch of the imagination but we have the building blocks in place.

"We would have like to have played with more width and if the space isn't there we have to go through the middle. We asked a lot of questions of the opposition and didn't take them. We are getting better and are hopeful the weather Gods are kind to us this weekend."

Divine intervention would be an added bonus, but what England really need is Cipriani to emerge as a genuine world-class No10 capable of pulling the tactical strings against the best in the world.

Of course, he cannot win the game on his own and the England pack, so inconsistent against the Wallabies, has to front up as well. Collectively, the team have to show better discipline and trust their defensive system to halt South Africa without handing over cheap points through penalties - something they didn't manage against Australia.

South Africa have made two changes to the team which beat Scotland - Jannie Du Plessis has come into the front row while starts at flanker.

They join a Springbok side in need of a long, relaxing break - and it's Cipriani's job to send them packing.