England 183 for 5 (Bairstow 86*, Linde 2-20) beat South Africa 179 for 6 (van der Dussen 58, S Curran 3-28) by five wickets

Jonny Bairstow's highest T20I score carried England to a final-over victory over South Africa in the first T20I in Cape Town.

Most players perform at their best when they feel valued and secure. But others - notably Kevin Pietersen in 2012 - seem to be at their best when they have a point to prove.

Bairstow appears to fit into this second category. Having forged an excellent reputation as an opener in ODI cricket, he would have been understandably disappointed to be demoted to No. 4 in the T20I team as England preferred Jason Roy and Jos Buttler at the top of the order. Having already seen his Test career falter after he was asked to move up the order and relinquish the gloves, he could be forgiven wondering if history might be repeating itself.

But from his first delivery - when he quite beautifully threaded the field with a dab to the third man boundary - he looked in imperious touch. And if there were times he hit the ball murderously hard - a heaved six over long-on off the back foot from deep inside the crease off Tabraiz Shamsi - there were also moments, such as when he guided the ball behind point with precision, when he demonstrated his touch and timing.

England were in some trouble during Bairstow's early moments at the crease. While South Africa made 57 for 1 in their six-over Powerplay, England were restricted to just 34 for 3, with all those promoted above Bairstow dismissed.

For a while, as Bairstow and Ben Stokes thrashed the ball around Cape Town, memories were revived of their vast stand of 399 in the New Year Test of 2016. On this occasion they added 85 off 8.4 overs, until Stokes heaved a long-hop down the throat of long-on and England's innings stalled. With 25 balls remaining, they still required 55.

But a nine-ball over from Beuran Hendricks - the 17th of the innings - was taken for 28 runs by Bairstow to put England back on track. And while Lungi Ngidi conceded just five and took the wicket of Eoin Morgan from the 18th, the nerveless Sam Curran thrashed his second ball for six off the faultless Kagiso Rabada to keep England in the hunt.

Even then there were seven required from the final over. But with Bairstow pulling the first ball of the over for four and carting the second for six over mid-on, England clinched a five-wicket victory with four deliveries remaining.

Whether this proves Bairstow's point - that he belongs at the top of the order - or the team management's - that he can play an important role in the middle-order - is debatable. But by producing a high-class innings and also seeing his side home, Bairstow must have gone a long way towards making his place in the side safe.

Linde's fine start

Given the pace options available to South Africa, you wonder how much time England gave to thinking about the left-arm spin of George Linde ahead of this match. As it happened, though, Anrich Nortje - the quickest bowler at the IPL - was omitted so South Africa could include two spinners in Linde and Shamsi.

Linde, on T20I debut, enjoyed a particularly impressive day. Bowling two overs in the Powerplay, including the first of the innings, he gained a surprising amount of turn and, having dismissed Jason Roy, edging an attempted cut, from the second ball of the innings, had the world's top-rated T20I batsman, Dawid Malan (brilliantly) caught sweeping a few minutes later. In all, he conceded just 20 runs from his four overs - the most economical return in the match - and contributed with that bat, too, hitting 12 from six deliveries at the death.

Tom Curran fails to take chance

At the start of this year, Mark Wood bowled with such pace and hostility in South Africa - albeit in Test cricket - that it seemed hard to imagine a scenario where England would leave him out. Since then, however, he's spent more time carrying drinks than charging in and was recently given just a limited-overs central contract. Sometimes it seems England don't appreciate quite what a gem they have in Wood.

Sure enough, he was left out again here. But, in a funny way, his case for selection might have been made for him by the struggles of the man who won the nod ahead of him. For Tom Curran conceded 55 here - his worst T20I figures - including four sixes. None of his colleagues conceded more than one six and there were only seven in the South African innings.

Curran started well enough. His first ove in the Powerplay cost only three. But his second was plundered for 24 - the most expensive of his T20I career - as Faf du Plessis appeared to target him.

It wasn't that he bowled especially poorly. It was more that, without the extra pace offered by the likes of Wood, his control of length has to be immaculate. But here he bowled either short or on a length and, without much variation from his cutters, was carted for each of those sixes over the leg side. With England using this series in the hope of settling upon a T20 World Cup line-up, it may have proved an expensive evening for Tom Curran.

Sam Curran shines

It was a much better day for Sam Curran. After winning the race for selection against Moeen Ali - in truth, after the impressive IPL Curran enjoyed, he was always going to play - he took the new ball and took a wicket in the first over. His two Powerplay overs cost a respectable 13, with four of those runs coming from an edge just wide of slip.

But it was his bowling when he returned for the 14th over that was most impressive. Going round wicket, cramping the batsmen for room and demanding they attempt to hit to the longest boundary, he claimed two more wickets - his 3 for 28 was the best return of his brief T20I career - with an accurate and surprisingly sharp bouncer complemented by cutters that left the batsmen struggling to settle against him. Later, his six from the penultimate over calmed England's nerves just as it appeared South Africa could hold on.

Afterwards Curran reasoned that the regular cricket he had enjoyed at the IPL going into this series had given him something of an advantage in terms of rhythm. But it was another remarkably mature performance from a 22-year-old who already seems to have been around for years.

George Dobell is a senior correspondent at ESPNcricinfo