Eoin Morgan has insisted that he would have continued to view Jos Buttler as a top-order batsman in T20 cricket even if he had failed for a third time in the series in the final T20I at Durban, describing him as one of England's "greatest-ever white-ball cricketers" and comparing him to AB de Villiers.

Buttler's batting position has been a constant point for discussion throughout the series. Since Rajasthan Royals promoted him to the top of the order in May 2018, he has opened in 31 out of 32 T20 innings, including each of his last eight games for England.

While few doubt the fact he is a destructive player opening the batting - he has averaged 44.58 with a strike rate of 154.66 in the role since being moved up in the IPL - there is a school of thought that suggests England's wealth of top-order options but dearth of finishers means that he would be best used as a floating middle-order batsman.

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But Morgan has insisted throughout this series that Buttler is used best as a top-order player, saying that he did not view his 29-ball 57 at Durban as vindication. "If he'd failed today, he still would have been considered in the top three," he said.

"He's a very fine player. He's got unbelievable ability to take any bowling line-up apart, and to have somebody in your side like that is great. I don't think he played that well today, but he got a score on the board, and set a really good platform for us to try and chase a score down along with Jonny [Bairstow].

"[Jos is] one of our greatest-ever white-ball cricketers," Morgan told Sky Sports. "I realise why people talk about him so much, but not in a negative way. I think he has as much talent as someone like AB de Villiers.

"It took AB de Villiers a long time and a lot of games to actually get going in a South African shirt. We need to back guys that have that sort of talent, and Jos Buttler's been around a long time now, and we know when he delivers, we win games of cricket."

"At times you can be the victims of your own mentality, so we said we're not going to leave anything in the tank at the halfway stage, and we didn't" Eoin Morgan

Morgan admitted that the plan to use Buttler at the top of the order could change between now and the T20 World Cup, which starts in October, but maintained that the top three's ability to break the back of a run chase and to lay a platform on which the middle order can build was crucial.

"I think the priority at the moment is to get the top three [Buttler, Jason Roy and Bairstow] as many balls under their belt as they can," he said. "They're the most destructive players that we have. If that changes between now and the World Cup, and we feel the need to fill a gap somewhere, then we might change it, but for the moment it's an extremely destructive batting line-up to play against.

"The advantage that we have now is we have guys going away, playing Pakistan [Super] League, IPL, they'll come back and play in the Blast, then play in the Hundred. So there's a lot of T20 fixtures, [of a] high-quality standard, that we do look at - guys in pressure moments, how they deliver.

"We encourage our guys, particularly our senior guys, or guys who are trying to get into our squad or final XI, when they go to tournament like that - they need to go and try and be MVP, leading run-scorer, take the most wickets, stand out, be the man. So when they come into international cricket, it's not a surprise."

Morgan accepted that England had "not played our best cricket" throughout the series, and suggested that they were "rusty" in the first T20I at East London, but said that he was always confident that his side could chase down an imposing target of 223 in the final game.

"[It was] an absolutely belting wicket with really short boundaries - a real bowler's graveyard, so to speak," he said. "Our bowlers kept it within something chaseable, and at the halfway stage we talked about 2016, when we chased down 230 against South Africa in the second game of the World Cup. At times you can be the victims of your own mentality, so we said we're not going to leave anything in the tank at the halfway stage, and we didn't."

Despite a troublesome back leading to suggestions he might step down as England's white-ball captain after the 50-over World Cup win last summer, Morgan has been in imperious form since that triumph. In his last eight T20I innings, he has hit 328 runs off 179 balls, averaging 54.66 with a strike rate of 183.24, and matched his own record for the fastest half-century by an England batsman at Centurion with a 21-ball effort.

"Not bad," was Morgan's own assessment of his form. "I've not been working on a great deal of stuff," he said, "mainly just keeping my head clear, and being precise about what I'm trying to do, trying to work with the guy at the other end the whole time [and trying to] marshal the troops a little bit."

As a captain, Morgan has continued to work closely with England's white-ball analyst, Nathan Leamon - "trying to make little fine adjustments" - and explained that his regular use of Moeen Ali in the Powerplay was an attempt to target Quinton de Kock's relative weakness against offspin.

"There's a gambling element as well, a bit of risk/reward. We've seen that throughout the series, trying to get Quinton and Temba [Bavuma] out. It's not easy at all, but continuing to bowl Moeen while Temba's taking it easy at one end and Quinny's taking him on, the odds are in our favour whether he gets hit or not. My gambling does come into it a little bit."