After a devastating defeat to a Chris Gayle-inspired West Indies in their opening match, England's World Twenty20 chances would have been hanging on a knife-edge had they not reversed a run of five straight defeats against today's opponents.

The signs were not good when the rampant South Africans struck 229-6 off their 120 balls, led by 58 from another of the world's best all-round batsman, Hashim Amla, along with half-centuries from Quinton de Kock and JP Duminy.

At the time, that was the second-highest score at a World Twenty20.

England responded in kind, however, as Jason Roy began proceedings with a ferocious 43 from 16 deliveries.

Roy and his fellow opener Alex Hales amassed 44 off the first two overs of the innings, the most in international Twenty20 history.

Root, one of the most elegant and consistent players in Test cricket, then abandoned style for substance as he blitzed 83 off 44 to take England within touching distance of the total they were chasing.

He was eventually out as England lost two more wickets in the last over before Moeen Ali sealed victory with just two balls to spare. 

It marked the biggest run chase in World Twenty20 history for the 2010 winners and the second biggest ever in the international game after West Indies scored 236-5 against South Africa in Johannesburg in January 2015.

"We knew we just had to back the natural instincts and play good cricket shots," said Root.

"After the start we got, we couldn't have asked for better, it made the middle order a lot easier and put South Africa under pressure straight away, which is exactly where we needed to be."

New Zealand had earlier ensured an equally thrilling eight-run victory over Australia in the opening match of the day at the HPCA Stadium in Dharamsala, gaining revenge for their defeat in last year's 50 over World Cup final.

The Black Caps could only manage 142-8 batting first, a total which appeared woefully underpar as Australia cruised to 37-0 after four overs.

Led by 3-17 from Mitchell McClenaghan, New Zealand fought back as their neighbours and fiercest rivals crumbled to 134-9. 

As in their opening day victory over hosts India in Group 2, New Zealand's spinners were decisive, with Mitchell Santner taking 2-30 and Ish Sodhi conceding just 14 runs off his four overs.