Cape Town - England skipper Joe Root refused to use illness as an excuse for their loss following their 107-run loss to the Proteas in the opening Test at Centurion on Sunday.
England, who started the fourth day on 121/1, needed to chase a 255 to win the first of four Test matches.
The visitors were stumbled all out for 268 with Kagiso Rabada leading the South African bowling attack with figures of 4 for 103.
Illness has swept through the England dressing room, which saw several players put in quarantine at the team hotel over the weekend.
Root also joined the sick list, leaving the field for 40 minutes during the morning session of day three on Saturday.
The England skipper insisted that the illness in the dressing room did not affect their performance on the field.
"There has been illness and there's been a lot thrown at the squad for the last week," Root told reporters in Pretoria.
"I think everyone has dealt with it the best they could, there are certain things that you can and can't control.
"Throughout the week, we've looked very well in making sure that it's not affected as much as you can."
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Root is positive that England will bounce back in the second Test, which gets underway on Friday at Newlands.
"It's frustrating but ultimately it's happened now," said Root.
"It looks like the illness is through the camp and we can be fine and fit and ready to go for Cape Town and bounce back really quickly from this week."
- Compiled by Lynn Butler