Third Test, Trent Bridge, day two (stumps): England 445; South Africa 84-2
England gained an advantage in Friday's final session by removing South Africa's prolific openers to expose the middle order on a pitch that is becoming very tough for batting.
Graeme Smith, who had hit a double-century in the first innings of both previous Tests, trod on his own stumps to be out hit wicket.
And if James Anderson's plausible appeal for lbw against Jacques Rudolph just before stumps had been upheld, South Africa would have been in trouble.
Earlier, Alec Stewart hit 72, his first half-century of the series, taking England to a fine total on a wicket where the bounce is becoming more variable by the hour.
Nasser Hussain and Ed Smith both scored quickly in the first half-hour of the day.
Debutant Smith began the day on 40 but was soon into his stride and after reaching his half-century he played one glorious cover drive off the back foot for four off Shaun Pollock.
It was Pollock, however, who took South Africa's first wicket of the day when Hussain, who had moved from 108 to 116, fell lbw to a fine off-cutter.
Smith (62) nicked a Jacques Kallis delivery before Andrew Flintoff (0) edged his 20th delivery, bowled by Andrew Hall, straight to first slip.
When Ntini returned for a second spell just before lunch, Alec Stewart hit two boundaries in a single over and reached lunch on 30 not out.
He scored slowly after the interval, however, allowing Ashley Giles to hit 22 before becoming the third man to be dismissed by Hall.
But when Ntini bowled James Kirtley for a single, Stewart launched into a flurry of scoring off Ntini and Paul Adams.
A stand of 32 for the ninth wicket with Steve Harmison (14) ensued before both men fell playing attacking shots off the left-arm googlies of Adams.
Michael Vaughan gave Kirtley and James Anderson the new ball, but it was only when they were replaced by Harmison and Flintoff that things started happening.
In his second over, Harmison persuaded Herschelle Gibbs (19) to edge onto his stumps.
Then Flintoff was rewarded for some brilliant bowling against Smith when the South African skipper self-destructed on 35.
Rudolph and Jacques Kallis had to weather lbw appeals and some very poor bounces to ensure there would be no further damage before stumps.
England: MP Vaughan (capt), ME Trescothick, MA Butcher, N Hussain, ET Smith, AJ Stewart (wkt), A Flintoff, AF Giles, SJ Harmison, JM Anderson, RJ Kirtley.
South Africa: GC Smith (capt), HH Gibbs, JA Rudolph, JH Kallis, HH Dippenaar, N McKenzie, MV Boucher, SM Pollock, AJ Hall, PR Adams, M Ntini.