England skipper Alastair Cook believes his side are far from the finished article, while opposite number AB de Villiers thinks they will be the team to beat.

The 2-1 series victory meant it was a time for celebration for England at Centurion on Tuesday, but the underwhelming display in the final match, which saw them lose by a crushing 280 runs, might be cause for concern further down the line.

They haven’t won a dead rubber since beating India in 2011, and it also means they’ve only won two of their last eight Tests.

‘It was frustrating,’ said Cook after the match. ‘It shows when you’re not quite there mentally. The real desire was  missing, coming down from a high. But if you’d said eight weeks ago that we would stand here at 2-1 we’d be more than happy. This game showed South Africa are not as bad a side as everyone are saying so we must have played some good cricket.’

Man of the Series Ben Stokes’ double century at Newlands and Stuart Broad’s spell of five wickets for just one run in Johannesburg showed that England have players that can change the course of the game in a session, but Cook feels that the ability to put in efforts like that consistently is what is missing from the side at the moment.

‘This side has got the ability to win games quickly, but we’re still a long way away from this side reaching its potential. We’re a dangerous side to play against, but in order for us to go to the next level we need to be more consistent and not have as many off days.’

Proteas skipper De Villiers was quick to praise England for their performances throughout the series, adding that they have the potential to be the best.

‘I want to give them a lot of credit for the way they’ve played,’ he said. ‘They completely outplayed us in the first two Tests, no doubt. They’re possibly the team to beat in the next year or so. They have a lot of experience, a lot of match winners and the future is looking bright for their side. They have a very stable captain in Alastair Cook and have a good two years to come, where they will be a force to deal with.’

Proteas coach Russell Domingo singled out Ben Stokes as the decisive player, likening him to Jacques Kallis.

‘England are very fortunate. They’ve got Ben Stokes who gets hundreds and takes five-wicket hauls,’ he said. ‘He gives them what South Africa had a year or two ago: four frontline seamers and a spinner. Jacques Kallis used to do that for South Africa, it’s a massive factor.’