Australian team captain Lleyton Hewitt took a big risk in the doubles game against Great Britain when he overlooked specialists Chris Guccione and John Peers in favour of the mercurial Nick Kyrgios and Alex de Minaur to secure a place in the final eight ATP Cup.

The Australian pair faced doubles specialist Jamie Murray (ranked 20th in the world in doubles and the older brother of former world number 1, Andy Murray) and Joe Salisbury, on Thursday in Sydney, and beat them in a tight, hard-fought encounter.

When playing for himself, Kyrgios is an unknowable quantity – he can be either extremely good or seemingly determined to belittle the talent he so obviously is blessed with. During the ATP Cup he has been lethal. He beat Germany’s Jan-Lennard Struff. He then completed a three-set triumph over world number 6 and Greece’s darling Stefanos Tsitsipas who just two months ago won the ATP World Tour Finals.

English tennis writer Stuart Fraser tweeted of Kyrgios’ earlier performance when he obliterated Cameron Norrie in his quarter-final singles’ match: “If they could convince Nick Kyrgios that the Australian Open is a team event, then he would win it. Terrific performance in Sydney to beat Cameron Norrie 6-2 6-2 and put Australia 1-0 up against GB in the ATP Cup quarter finals.”

Kyrgios’ doubles teammate, De Minaur (ranked 18th in the world), however, unexpectedly lost his singles’ match against Dan Evans, so things teetered on the edge for the doubles. The Australians had to win if they were to progress to Saturdays semi-final.

And when the first set was lost 6-3 to the British pair, it needed the calming presence of Kyrgios to steady the ship – it is not a role one would have attributed to him but that is exactly what he did. The next set Australia won 6-3.

So it all revolved around the match tiebreak – where the steady nerves of a gunfighter at noon are most needed. Kyrgios and De Minaur kept it together and faced down four match points to take the set 18-16.

On Saturday, Australia will face either Belgium or Spain who fought it out on Friday. If it is Spain, then expect fireworks between Kyrgios and world number one Rafael Nadal . They have a “history”. The Aussie who is ranked 29th has a way of getting under the skin of one of the world’s greatest and most feared players.