Graeme Swann believes England must beat India at home and away if they are to fulfil their ambition to be one of the best one-day international nations in the world.
Andy Flower, the team director, has targeted an improvement in the 50-over game - England are currently ranked fifth - after guiding his side to the top of the Test standings.
England are favourites to win the series against an injury-depleted India, who are without most of the team that won the World Cup in April, as the hosts lead 1-0 heading into Friday's third game at The Oval. While Swann is focused on a series victory, he said any longer-term ambitions will only be realised if England also win in the return series on the subcontinent next month.
"Our official ranking is five and I don't think we can argue with that," he said on Sky Sports News.
"We have shown some improvement recently but we have to continue that if we want to be one of the best teams. We have to beat teams like India, not just in this series, but when we go away to play them as well."
Swann said that Alastair Cook, the one-day captain, is silencing his doubters after his match-winning innings in the rain-shortened win on Tuesday.
Cook's suitability for the shorter formats had been questioned when he was installed as captain earlier this summer, but he responded with an unbeaten 80 off 63 balls in Southampton. "He's just letting his bat do the talking," Swann said. "It is very good for Cooky. He was written off - he's even hitting sixes these days."