South Africa coach Peter De Villiers claims Martin Johnson has transformed England into a team to be feared with less than 10 months to go until the Rugby World Cup.
England head into Saturday's Twickenham showdown with the Springboks ranked fourth in the world after securing home and away victories over Australia and a tough 26-13 win against Samoa.
Johnson's men also produced an encouraging performance in defeat to New Zealand earlier this month, particularly up front where England won the scrum battle.
In contrast, De Villiers is under growing pressure after the Springboks, who finished last in the Tri-Nations, lost to Scotland at Murrayfield last weekend.
South Africa scraped wins over Ireland and Wales earlier in the tour but De Villiers believes England will pose their toughest challenge.
"Martin has made England a world force again. It is a hell of a worrying factor for us, especially with the World Cup so close, that they are gelling as a team," said De Villiers.
"We will always respect them and it is good for world rugby if England rugby is strong. They are definitely the best scrummaging side in the world now.
"They have annihilated every side they have faced in the scrum. A full Twickenham will ensure that this is the toughest Test of the tour for us.
"There is always pressure in this job. There are 22 players around you but there are the hopes of 43 million people at stake in every game.
"You never get used to it. Saturday's performance wasn't a true reflection of the talent in this squad and the players want to put that right and end the Test season on a high."
South Africa have made two changes from Murrayfield, with Ulster scrum-half Ruan Pienaar and number eight Pierre Spies both recalled.
England are set to name the same side that beat Australia in record fashion two Saturdays ago, with the only change likely to be on the bench with Matt Banahan in line to replace Delon Armitage.
Johnson, who will confirm his line-up tomorrow, expects a fierce Springbok backlash from Murrayfield - but he backed England to meet that challenge head on.
"There is nothing better than getting that intensity of a Test match in your legs, your lungs and your brain. We have moved up every game," said Johnson.
"We are in a good place. Good teams play well every week. Good players play well every Test match.
"We are going to have to play very well to beat South Africa.
"They will come to Twickenham and bring all they have got. That is the challenge, let's relish it and see how we stand up."
The last time South Africa played at Twickenham immediately after losing to Scotland was in November 2002 and they were thumped 53-3.
Corne Krige led his team on a trail of destruction that day as South Africa lost all discipline and lock Jannes Labuschagne was sent off in the 23rd minute.
Despite the pressures on De Villiers, Johnson does not expect the current Springbok team to implode in the same way.
"They won't collapse under the pressure, put it that way," said Johnson.
"They are world champions and they still have a lot of experience in the group.
"They have a huge amount of pride in being the Springboks, as we do with England."Reuse content