Rustenburg - John Terry has described the loss of injured captain Rio Ferdinand as "devastating" but the Chelsea defender is confident England have enough defensive strength to keep their Soccer World Cup challenge on track.?

Ferdinand, who suffered knee ligament damage in a training ground collision with Emile Heskey last week, cut a forlorn figure at England's training camp on Tuesday morning.

As his team-mates went through their paces on a nearby pitch, the defender sat glumly on a chair, his left leg immobilised by a protective brace.

Ferdinand will stay with the squad until Saturday's Group C opener against the United States but will then fly home to continue his recovery under the supervision of Manchester United's medical team.

Ledley King is expected to take his place in England's starting line-up alongside Terry, who praised his injured team-mate for his decision to stay with the squad.

"It is devastating to lose Rio," Terry said. "I was looking forward to playing alongside him.

"He has picked up an injury that was no-one's fault in training. It was one of those freak accidents that happen occasionally. It is just disappointing that it has happened to our captain and one of our most influential players."

Terry said Ferdinand's decision to stay on in South Africa had helped to bolster morale in the squad.

"It is great for him to be out here and still want to be part of the squad," Terry said. "He realises we still have a very good chance. If we can go a long way a lot of that will be dedicated to Rio."

England have failed to impress in their warm-up matches and have not produced a really convincing performance since a 5-1 win over Croatia in September 2009.

But Terry played down concerns over the build-up, arguing that every side would need time to adapt to the new ball being used for the tournament, playing matches at altitude and the unique atmosphere inside South African stadiums.

Monday's win over local club Platinum Stars in Moruleng - higher even than Rustenburg, which is 1 500m above sea level - had been worthwhile in that sense, he said.

"There are going to be problems with the ball for every team," Terry claimed. "It moves about in the air and off the surface.

"It is something we are trying to work on each day and trying to improve upon. A couple of times on Monday night it swerved at the last minute.

"There is nothing we can do about that. We just have to try and deal with it the best way we can. At the same time we have to try and get crosses into the box and have a lot of shots so that we cause problems at the other end."

The match in Moruleng offered England a first experience of the vuvuzela-powered cacophony that a South African crowd can generate, but Terry does not believe the traditional horns will affect players on the pitch.

"The vuvuzelas are not a problem," he said. "It was quite loud sitting there listening to them in the second-half but on the pitch it is not a problem."

Terry added: "We have had a few days to get used to the ball and the conditions and the altitude. We have done that.

"The altitude has been more of a surprise than anything. Your mouth is really dry. We train at quite a high level anyway but Monday was another 150 metres above sea level again. We certainly felt it.

"But the manager chose the right game at the right stadium at the right time. It was a real good work out. We needed that."