England 328 for 6 (Sciver 119*, Davidson-Richards 107) lead South Africa 284 (Kapp 150, Cross 4-63) by 44 runs
Centuries for Test debutant Alice Davidson-Richards and stalwart Nat Sciver turned England's innings around and put the hosts back in control of their contest with South Africa in Taunton.
Friends since their school days at Epsom College, where they played cricket, hockey and netball together, the two rescued their side from a precarious position at 121 for 5 with a record sixth-wicket partnership for England Women in Test cricket. Worth 207 runs, it was also their joint second-highest stand for any wicket and it took the side to 328 for 6, a lead of 44 runs.
At the age of 28 and making her first England appearance since she played six white-ball games in 2018, Davidson-Richards became the second England player after WG Grace to score a century and take a wicket on Test debut after she had Nadine de Klerk caught behind on the first day.
She was resolute in supporting Sciver to her fifty, brought up with a lovely drive for four through mid-off. Davidson-Richards had nine runs from 45 balls before driving Nonkululeko Mlaba through the covers for her first four.
By tea she had struck four more boundaries and of the 17 she had scored by the close, the best was arguably her delicious cover drive off de Klerk to move to 75, holding her pose and shaking her bat in in approval as the ball sped to the rope. That was before her gloriously timed punch in front of point to bring up her century before she was met with the warmest of hugs from Sciver.
When Sciver had raised her century a little earlier with a scampered single off Marizanne Kapp, Davidson-Richards celebrated just as enthusiastically as her team-mate, pumping her fist and jumping into the air as Sciver removed her helmet, raised her bat and acknowledged the applause from the stands.
It was Sciver's maiden Test hundred in her eighth match and continued a rich run of form that played a key role in her side finishing runners-up at the World Cup in April, where she scored unbeaten centuries against Australia in England's opening match and again in the final.
It also came in the midst of a tense match situation. After England had reduced South Africa to 45 for 4 on the opening morning, Kapp's brilliant 150 carried them to a respectable total of 284 by the close. In reply, England began brightly, their new opening pairing of Tammy Beaumont and Emma Lamb, another of England's four Test debutants, putting on a 65-run stand as the South African bowlers struggled to hit the right lengths.
But then Anneke Bosch trapped Beaumont lbw playing round one that swung away late and struck her on the toe in line with middle and leg stump and followed up with the wicket of Lamb for an accomplished 38 with a gem of a delivery that nipped back in off the seam and through the gate to uproot off-stump.
Kapp should have had Heather Knight's wicket shortly before lunch, but wicketkeeper Sinalo Jafta dived across first slip and Sune Luus, poised for a catch that looked sure to be hers, spilled the ball in the confusion.
As it happened, Knight fell without adding to her score of 8 on the first ball after the break, caught short of her ground despite a desperate full-length dive after Sciver had turned a de Klerk delivery towards square leg and called for a single. The slightest of hesitations mid-run from both of them proved crucial as Tumi Sekhukhune fired the ball to Jafta, who removed the bails at the striker's end.
Bosch then claimed her third wicket when she invited Sophia Dunkley to drive with a fuller ball just outside off stump, finding the edge which sailed to Andrie Steyn at slip.
In the next over, Mlaba bowled Amy Jones for duck with an excellent ball tossed up on middle stump and straightening as Jones chopped onto her stumps and England looked to be in serious trouble still 163 runs behind.
But from there Sciver and Davidson-Richards set about their task with great class, Sciver unbeaten on 119 when, off the last ball of the day, Davidson-Richards sent a straightforward catch to Lizelle Lee at backward point off Sekhukhune.