Johnson laments England failings
The Springboks extended their winning run over England to seven Tests with a 21-11 victory, courtesy of tries from replacement flanker Willem Alberts and wing Lwazi Mvovo. Fly-half Morne Steyn also kicked 11 points as England failed to cope with the Springboks' physicality.
"There were too many mistakes today. Some of them were forced by their pressure but you can't compound them and let the opposition keep coming at you," said Johnson.
"We just invited pressure back onto ourselves. Test match rugby is pretty basic and pretty simple but you have to execute the fundamentals under pressure.
"Too many times today we didn't secure the ball. Those errors just hurt us. We were turning over pressure too cheaply.
"It is a fundamental of Test rugby - if you make the mistakes we made all over the field, give penalties away then you invite pressure back on yourself.
"The reality is that if you don't do the fundamentals of Test rugby for 80 minutes you don't deserve to win."
England lost fly-half Toby Flood and flanker Tom Croft to injury before half-time while Chris Ashton played on despite taking a blow to the head in a collision with Victor Matfield, which left the Springbok captain with a broken rib.
"They are a big heavy physical team. It was a real tough end-of-series Test match, there were some big hits going in," said Johnson.
"We lost a couple of players which was a disruption but we have got to handle that too. If you are not getting the breaks you have got to handle it and not aid the process by turning the ball over."