A superb unbeaten century from Kevin Pietersen put England firmly back in contention in the second Test against South Africa at Headingley.
Pietersen finished the third day on 149 as England reached 351-5 in their first innings at the close, a deficit of 68.
Pietersen and debutant James Taylor shared a fifth-wicket stand of 147, hauling England out of a precarious position at 173-4.
South Africa had dominated the series almost entirely up to that point, but Pietersen finally put together a knock worthy of the number one Test side.
Taylor had made a composed and watchful 34 off 104 balls before he was somewhat unfortunate to get an inside edge to a full delivery from Morne Morkel which ricocheted into his off stump.
With 40 minutes of an elongated day left to play, England decided against a nightwatchman and Matt Prior joined Pietersen in an unbeaten stand of 31 to the close.
Pietersen's onslaught after tea, as Morne Morkel tried to test him with the short ball to a deep-set field, included six fours from only 11 balls.
Morkel and Dale Steyn were taken out of the attack, and South Africa were forced on the defensive as Pietersen brought up his 21st Test hundred in 142 balls, but he needed only 52 of those for the second 50 - pulling and driving 17 fours on his way to three figures.
He operated on a different level to those who had batted before him on a fair pitch, but one which had appeared to preclude dominant strokeplay unless the bowlers dropped short.
Pietersen, who had shared a hard-working half-century stand with Jonathan Trott for the third wicket, took England seamlessly past the second new ball in a partnership of 147 with Taylor.
On a surface already beginning to offer variable bounce to the seamers, it seemed Pietersen would have to dig in after Alastair Cook and Andrew Strauss had gone either side of lunch.
Cook chanced DRS, after being hit in front as he pushed forward to Vernon Philander. But Steve Davis' lbw verdict was vindicated when Hawkeye confirmed the ball pitched on leg-stump and straightened to hit middle halfway up and end an opening stand of 65.
Strauss and Trott kept South Africa at bay either side of a downpour which wiped out more than half the morning session and brought an early lunch.
But Steyn gave the England captain no leeway in early afternoon, and was rewarded when Strauss got a thin edge behind on the back-foot defence.
Pietersen and Trott then had to employ the patience Petersen had demonstrated for so long for the tourists.
The return of Steyn was too much for Trott, who edged an attempted cut low to slip - where Graeme Smith took a neat catch, for a dismissal which was a near action replay of Jacques Kallis' to James Anderson on Thursday.
Morkel sought to discomfort Pietersen, as he had successfully at The Oval last week, with his pace and bounce. But this time, England's mercurial number four had set his mind on the long haul.
The same could not be said for Ian Bell, who pushed out without foot movement at a full-length ball from Kallis and edged to Smith at slip.
Taylor was therefore required to bat for seven minutes to help close out the session. He duly did so, with the bonus of an off-driven four off Tahir to get off the mark.
After tea, Taylor's Test introduction was largely in an observer capacity as Pietersen took over.
He completed his half-century with a pull for four off Steyn, and then gave his only chance two runs later when he clipped Morkel straight to short-leg - where Hashim Amla could not hold on to a sharp half-chance.
Pietersen then clubbed the next two balls dismissively to the midwicket boundary, to signal the start of his one-man counter-attack.
Taylor proved an able assistant, as Pietersen continued his often brutal treatment of one of the world's best attacks.
England's new number six would have been short of his ground for a scampered single on 24, had Amla hit the stumps from midwicket. But otherwise, he was the perfect foil of reliability and calm until he edged Morkel on to his stumps.
Pietersen saved some of his absolute best until after his hundred was in the bag - a near straight-batted pull for four wide of mid-on and then straight six, in the space of three balls, off Steyn delighting a partisan full house and forcing Smith to withdraw his pace spearhead again.
When South Africa captain Smith hobbled off before stumps, having apparently injured his knee chasing a ball into the outfield, there was even the hint of suspicion that the nature of this table-topping series - not merely match - might have changed.