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.
"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.
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.
"We will always respect them and it is good for world rugby if England rugby is strong," he added. "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."