This current one-day series against New Zealand is the last chance for England players to make a case for a place in the Champions Trophy squad. In terms of leaving a favourable impression on the selectors, Joe Root could hardly have done any better with two half-centuries in two matches, including his unruffled matchwinning innings in Napier.

But instead of finalising plans in the selectors' minds his success may yet require them to rip up their original ideas. Heading into England's New Year one-day commitments, firstly in India and now in New Zealand, it was largely accepted that England's top five was set in stone: Alastair Cook, Ian Bell, Jonathan Trott, Kevin Pietersen and Eoin Morgan.

But England's rotation of senior players - Trott was rested for India and Pietersen is missing this series - has given Root an opportunity which he has made the most of. In Napier he became the first batsman to start his ODI career with six consecutive scores of over 30 and, even taking into account a friendly batting surface and reasonably friendly attack, it was an innings that any of the best finishers around would have been proud of. Needing seven-an-over does not worry a modern batsmen, but Root made it look like a Sunday stroll.

As ever, Cook would only say that it was a position he was pleased to be in. "That is a good sign. You always want these new guys pushing the seniors for places. It's a good problem to have. Joe can only keep doing what he's doing, scoring crucial runs."

Root has already shown himself to be a very versatile batsman, which is why his case for Champions Trophy selection is becoming stronger by the day. Being an opener in the first-class game means he is not adverse to facing the new ball but he has the invention in his strokeplay to manipulate the field later on. What he lacks in brute strength he more than makes up for in dexterity as he showed in Napier with the scoop over fine leg.

"He's played shots I didn't know he could play," Cook said. "He came in today when we needed seven runs an over, and played very well. The way he has handled himself in international cricket so far has been very good. A lot of playing international cricket is about temperament, and he's certainly shown the right attitude and been able to handle pressure."

The current top five all have plenty going for them. The captain is not going anywhere, and is developing into a high-class one-day batsman; Bell is averaging 55 with a strike-rate of 80 since coming back into the team and Trott's value is appreciated hugely within the side if not quite so highly outside it.

Joe Root made an unbeaten 79 Getty Images

Trott certainly puts the onus on other batsmen to make the running, which Root did on Wednesday, and a perfectly balanced top order would not have three similar players in the top three but, to beat a slightly broken drum, his record does not lose anything when compared to the likes of Jacques Kallis, Mahela Jayawardene, Kumar Sangakkara or Younis Khan.

Perversely, Pietersen's u-turn over one-day retirement has caused some headaches. England had actually started to plan, successfully as last summer showed, for life without him. That is not the same as saying they were happy not to have him, but sport moves on and the squad had started afresh.

The rotation policy has meant the ultimate decision over how he slots back in has been delayed. Remember, before he briefly gave the game away in May he had been opening the batting alongside Cook. Now that is Bell's role and with the new fielding restrictions - and two new balls - there is the belief Pietersen can be most effective at No. 4. Still, Root is not making a bad job of that spot right now. And it was a lack of desire for 50-over cricket that sparked Pietersen's problems last year. Does he really have the drive for it, even in a Champions Trophy year and with a World Cup in 2015?

If it is accepted that Pietersen's place is certain then that leaves Morgan, a player who has shown some of the best "closing" skills in the world but who has begun 2013 with a bit of a stutter in ODIs. He scored 94 runs in five innings in India, although that came off a 2012 home season where he averaged 74.50. And there are still few better, and calmer, judges of a chase.

Ashley Giles has shown he is not afraid to make significant decisions early in his reign. In all likelihood he has ended Craig Kieswetter's international career and Jade Dernbach faces a long road back to the one-day side. To a lesser extent, Samit Patel - another victim of Root's success - is being pushed back to the fringes. But if Giles finds a space in the top five for Root come June, and the opening match of the Champions Trophy against Australia, he will have made his toughest decision yet.