Danielle Wyatt's unbeaten 64 led England to a five-wicket victory over India that sealed the women's Twenty20 series with a game to spare.
England were cruising in their chase of 112, only to slip from 45-1 to 56-4.
But Wyatt batted with composure, sharing 47 with Lauren Winfield (29) to get the tourists home with five balls to spare in Guwahati.
Earlier, Katherine Brunt took three wickets and Linsey Smith two as India were restricted to 111-8.
The third and final match of the series is on Saturday.
England lost the one-day series in Mumbai 2-1, but have thoroughly outclassed India in the shortest form of the game.
After Saturday's match, they will move on to Sri Lanka for three one-day internationals and three T20s.
Pace bowler Brunt and spinner Alex Hartley will remain with the squad for that leg of the tour following injuries to Sophie Ecclestone and Georgia Elwiss.
Wyatt made her T20 international debut back in 2010 - but did not pass 50 until 2017
Wyatt, 27, had not passed 50 in any of her first 70 T20 internationals, but now has two hundreds and four half-centuries from her past 20 innings.
Labelled "frustrating" by captain Heather Knight after her dismissal in the first ODI and dropped for the second, she returned for the third and seemed to have learned lessons with a controlled maiden 50-over fifty.
This was more of the same. Instead of her usual T20 aggression, Wyatt eased the ball into gaps and ran hard - her 55-ball stay contained only six fours.
She watched on as Amy Jones, Nat Sciver and Knight all fell in the space of four overs to spinners Poonam Yadav and Ekta Bisht, but rebuilt with Winfield, who herself is trying to carve a niche in the middle order after opening for much of her career.
Winfield provided the impetus, removing any tension with three boundaries in as many deliveries, but fell before the job was complete when she pulled off-spinner Deepti Sharma to deep mid-wicket.
Brunt arrived with nine needed, an equation that became two from the final over, with Wyatt driving Sharma down the ground to confirm victory.
Raj top scored for India, but took 27 balls to score 20
The home side looked to be responding to defeat in the opening match with aggression when Smriti Mandhana hit Anya Shrubsole for six over long-off from the first ball she faced and followed up with a similar maximum later in the same over.
But after Mandhana edged the excellent Brunt behind in the next over, England squeezed.
Brunt and left-arm spinner Smith reduced India to 34-3, with home hopes resting on veteran batter Mithali Raj. Raj took 27 balls to make 20 and, when she tried to accelerate, lofted Kate Cross to long-on.
By that point, she had been involved in the bizarre run-out of Sharma, who hammered the ball back into the non-striker's stumps and was looking for a single off the rebound, only to be sent back by Raj and be short of her ground when wicketkeeper Jones collected Shrubsole's throw.
England were sharp in the field throughout and also had the boost of the return of off-spinner Laura Marsh, playing on the tour for the first time after recovering from a side injury, while also featuring in a T20 international for the first time in three years.
As wickets fell at a steady rate, India's acceleration never came. After Mandhana's initial blitz, England's efficiency meant only 88 runs came from 18 overs, leaving a meagre total to chase.
Ex-India seamer Snehal Pradhan on BBC Test Match Special: "India have been outplayed and will be hard-pressed to avoid a second consecutive series whitewash in T20 cricket. Lots of questions will be asked about the batting and who is going to get those quick runs."
Former Middlesex captain Isabelle Westbury on TMS: "A dominant performance from England. Danni Wyatt now has a half-century in the ODI and T20 series. Both those innings were measured and controlled, knowing exactly what she needed to do."