After 48 and 3 at Lord's, he made 44 and 33 in a low-scorer at Headingley, then thrashed 189 off 182 balls in Manchester as England dominated a rain-ruined fourth Test. He finished with 22 and 73 at The Oval, helping to set up England's 49-run win and securing his status as their leading run-scorer for the series.

"Coming into the series, he was under quite a lot of pressure," McCullum said. "The great thing was he was able to block that out as much as possible you hope that's down to the environment the skipper's trying to create, and the sincere messaging.

"480 runs at a strike rate of 90 [88.72], against the best bowling attack in the world, against the Dukes ball, in an Ashes series: people don't do that, you know? As the skipper said: you look at what people's upsides are, what their best days are, what they're capable of achieving rather than focusing on things that might not be there. He's a case in point.

"I think we've seen someone really grow and mature and really develop over the last six weeks or so. I'm sure he'll be proud of the series he's had and won't get carried away, because that's the type of personality he is. It's great - not just for Zak, but also for other guys around the side and around county cricket. They know that when they get the opportunity, they'll get support."

"Their contrasting skills - which we've talked a lot about leading into the series - is pretty evident and it helps one another," McCullum said. "Ben Duckett's turned into a really serious player at the top of the order for us. Away from home as well, his game in sub-continent conditions you'd expect to really flourish, too."

McCullum said that squaring the series from two-nil down - while doubling down on their attacking style with the bat - proved the point that the approach he and Stokes have implemented gets the most out of England's players. "We have a certain style we try to exhibit every time we play," he said.

"I think for us, that is our best chance of winning. The skipper and I firmly believe that, and some of the performances we've seen are testament to that. Look, you're always trying to win, right? You just don't want to be bogged down in key moments by the result.

"What we are trying to do is allow ourselves to get in a space in our own minds where it allows your talent to come out. If you're weighed down by fear of failure or by external noise, all you're doing is suffocating that talent. It's as simple as that. For us, entertainment is a big part of it and how we play is a big part of it. But for sure, we want to win."

From one win in 17 when Stokes and McCullum took over, England have won 13 of their 18 Tests under new leadership. "You look back to when the skipper took over and to come in as well," McCullum reflected, "would we be able to take on a great Australian team - and they are a great Australian team - and go toe-to-toe with them?

"I think the answer is yes - and that's a tremendous confidence-booster for the group, but also testament to the investment to all the guys who have really gone quids-in with their belief in this side and the direction the skipper wants it to head. When you go two-nil down in a series and you've played some really good cricket, you know there's going to be some challenges.

"To come back from that and square the series two-two, both teams will be disappointed they don't end up walking away with the scoreline, albeit Australia walk away with the urn. We stayed true to that under the fiercest of pressure."