Terry hopes to revive schoolboy partnership with King
Defender John Terry concedes England have been out of sorts in recent games and says players are still adjusting to performing at high altitude.
England beat Platinum Stars 3-0 in a final warm-up before Saturday's World Cup opener against the United States.
Terry, who started alongside Ledley King in Monday's friendly, said: "We had one to two weeks off and you lose a bit of sharpness, but that's improving.
"The altitude has been more of surprise to me. Your mouth is really dry."
England were unconvincing as goals from Jermain Defoe, Joe Cole and Wayne Rooney secured victory over a limited Platinum Stars side in their final run-out before the World Cup begins.
But Terry said the players needed time to adapt to the altitude as well as the much-criticised World Cup football.
"We train at quite a high level anyway, coming here was another 150m higher again and we certainly felt that," added the Chelsea defender after win over the Platinum Stars.
"We're looking good. We needed this game to get used to the flight of the ball and the altitude."
England's game against the US will be played at altitude in Rustenburg, a venue 1403m above sea level.
If they progress to the last 16 stage, Fabio Capello's side will also have to play in thin, dry air.
As for the 'Jabulani' ball which will be used in South Africa, there has been plenty of criticism flying its way, particularly from the goalkeeping fraternity.
Spain's Iker Casillas and Italy's Gianluigi Buffon are among the dissenters, while England's David James has described it as "dreadful" and "horrible".
England midfielder Frank Lampard has come out in favour of the new and lighter football but Terry says it will cause problems for everyone.
"It's important we put in a lot of crosses in the box and get a lot of shots in from outside the box," said Terry. "It's difficult for the keepers."
It was important we got 45 minutes together in a real competitive game with Ledley
The friendly at Moruleng Stadium was the first time Terry had played alongside Tottenham centre-back King in an international match.
But Terry is confident the fledgling partnership can succeed, following Rio Ferdinand's exit with a knee injury.
"It was important we got 45 minutes together in a real competitive game with Ledley," said Terry, who played alongside King for Sunday league side Senrab.
"We had a good understanding. We used to play together at Senrab many years ago. The understanding has always been there and we've worked a few times in training."