Maia Bouchier hit a debut Test century and Nat Sciver-Brunt the fastest in women's Tests as England largely dominated day one of the one-off game against South Africa in Bloemfontein.
Opening batter Bouchier (126) reached three figures from 124 balls, while it took Sciver-Brunt (128) just 96 deliveries to secure her second Test ton, and second against South Africa after making an unbeaten 169 at Taunton in 2022.
The pair put on 174 from 172 balls for the third wicket before England declared on 395-9 late in the evening session.
Sciver-Brunt was eventually run out backing up as South Africa's Nonkululeko Mlaba tipped a drive from Amy Jones (39) on to the non-striker's stumps, around bagging figures of 4-90 with her occasionally erratic but often excellent left-arm spin.
The tourists suffered a collapse of 5-38 from 357-4 post-tea at a windy Mangaung Ova, with South Africa then reaching 17-0 in the six overs before stumps under gloomy skies.
England captain Heather Knight may be irked by the clatter of wickets but will feel her side are well on course to follow their victories in the preceding T20I and ODI series with success in the Test, having put a sizeable score on the board on a pitch that is offering assistance to seamers and spinners.
This match marks South Africa's first women's Test at home since 2002 but they would have been in no mood to celebrate two balls into the game when the lack of DRS probably cost them the wicket of Tammy Beaumont lbw for four, off Marizanne Kapp's bowling.
That technology is not in operation in Bloemfontein with Cricket South Africa prioritising its use in white-ball cricket - good news for Beaumont as she looked plumb, despite the on-field call of not out,
Beaumont added only 17 further runs to her total before heaving a short ball from Ayanda Hlubi (2-40) to midwicket but England's top order stitched strong partnerships - Bouchier forging stands of fifty or above with Beaumont and Knight (20).
The potentially game-deciding stand, though, was Bouchier and Sciver-Brunt's, with their runs forming the bulk of the 189 from 33 overs England amassed in an utterly dominant second session.
Knight was pinned lbw by Tumi Sekhukhune shortly after lunch and Bouchier, whose two sixes added to 22 fours, sliced Mlaba to slip close to tea and was well caught by Sune Luus.
In between it was all England as Sciver-Brunt displayed her class yet again and Bouchier made the most of being dropped by Kapp on 47 at deep square leg late in the morning session.
South Africa tightened up after tea and began to quieten the run-rate, helped by wickets falling as Mlaba had Danni Wyatt-Hodge (12) caught behind off a gem of a delivery, ran out Sciver-Brunt, forced Charlie Dean (8) to chop on and then had Jones pouched at long-off.
Jones' dismissal brought England's second Test debutant, Ryana MacDonald-Gay, to the crease with the 20-year-old playing in place of injured fellow seamer Kate Cross, who suffered a back spasm in the final ODI in Potchefstroom on Wednesday.
MacDonald-Gay was cleaned up by Kapp as South Africa took the new ball, with Sophie Ecclestone (21 off 28) bowled by Hlubi shortly before Knight's evening declaration.
Speaking to the BBC after the close of play, Sciver-Brunt said: "It was great fun out there. I'm very happy with the day's work. I don't think about the numbers when I am out there, so I didn't realise how quick the century was - the scoreboard doesn't have balls faced.
"I got off to a quick start and getting to three figures in around two hours was really pleasing. I felt settled out there and was able to get into the flow and not be too disjointed around the breaks, which can happen often. It was great to feel switched on and present in the game.
"It's always nice to bat with no restrictions in Test cricket and you are only batting against yourself. When you play white ball, you are always under pressure to score so to bat without those pressures is really exciting. It's a great format of the game that I enjoy.
"Maia [Bouchier's] innings was brilliant. She was calm from the outset and took it one ball at a time. She took the game on and was committed, and she did such a good job.
"Facing Nonkululeko Mlaba and Sune Luus was hard, and they bowled in some really good areas. It will be exciting to see our spinners bowl on this pitch. There was a bit of seam around as well which is good news.
"We would have taken the score at the start of the day. We are delighted as a side and had partnerships all the way through. We'll recuperate today and recover as well as we can ready for tomorrow."
Watch day two of the one-off Test between South Africa and England live on Sky Sports Cricket from 7.40am on Monday (8am first ball). Coverage is also on Sky Sports Main Event from 8am.
