Ceri Large's first-half double inspired England Women to a 20-13 win over their Welsh counterparts at Twickenham Stoop to set up a Women's Six Nations title decider next week against France.
Large touched down twice as England Women made it four wins from four to establish their championship credentials and put themselves in line for a first Grand Slam since 2012.
Wales were blown away by a fluid first-half English performance and though they led 14-3 at half-time, Robyn Wilkins' penalty gave Rhys Edwards' side hope.
And it was centre Wilkins who really applied the pressure after the break, scoring twice as Wales Women's dogged defence continued to force errors from the English.
England flew out of the traps, Large making inroads immediately in the centres and it took a strong covering tackle from Keira Bevan to stop prop Rochelle Clarke from close range inside five minutes.
The breakthrough though, was not far away and in stepped Large with her first score of the evening, just reward for England's territory and possession, charging over Alisha Butchers to put her side 5-0 ahead. Amber Reed converted.
Reed turned provider after 28 minutes. Her searing break left Sian Williams looking bewildered, while her instinctive off-load to Large sent the powerful centre over to complete her double.
It was Scott Bemand's women who continued to dictate the tempo, but they perhaps did not translate possession into points and Llandaff North centre Wilkins pegged England Women back just before time with a well-struck penalty.
Wales Women - much like their male counterparts - seemed a different side in the second-half, captain Rachel Taylor carried with real venom and Shona Powell-Hughes was increasingly to the fore.
After 49 minutes, Taylor then opted against three more points, choosing instead to scrum down in the shadow of England's posts.
The Welsh pack responded magnificently, driving the English women off the ball and when Elinor Snowsill charged down the attempted clearance, Wilkins pounced on the loose ball to make the score 14-8.
With 15 minutes remaining, England Women steadied the ship through a Reed penalty but Wales Women refused to capitulate.
Wilkins was again Wales' heroine when - in a carbon copy of Dan Biggar's Twickenham interception - the centre pressured excellently to pluck an England pass and gallop under the posts.
However, in a remarkable turn, 34-year-old prop Clarke, on her 109th cap, demonstrated remarkable determination to charge down Wilkins' conversion attempt.
England Women finished the game in the ascendancy, three times getting over the Welsh line only to be held up, but player of the match Reed put the result beyond doubt with a last-minute penalty.
England defeated New Zealand 49-46 to level up the three-match Series at 1-1 heading into the deciding match on Wednesday morning.
Sloane Stephens advanced to her first Grand Slam final at the US Open on Thursday night