"To a lot of people, this ODI series does not mean much but to the Australia players it means a lot.''
Two of the first three ODIs in the series were canceled because of rain, before England won in Cardiff on Saturday to leave the fifth match as the decider.
The two great rivals will resume hostilities on the return tour in Australia, starting November in the first Ashes test in Brisbane.
"I don't know whether it will have much impact on the Ashes back home but we get the flight back home tomorrow a lot happier as a one-day side certainly,'' Clarke added.
"The Ashes is still a way away but everyone is excited about that and the players are thinking about it already.''
For the fourth straight Ashes tour, the losers in the test series went on to win the ODI series. And it was no surprise that record continued this year with England playing an experimental limited-overs side with the 2015 World Cup in mind.
Their chase was undone by two costly run-outs early on, which removed Kevin Pietersen on the fourth ball of the innings and No. 5 batsman Luke Wright both without scoring.
"We've been competitive,'' England captain Eoin Morgan said. "We've learnt a lot about guys coming through. They showed a lot of promise. We've learnt they can step up to the mark.
"The nature of the international schedule is that it's hectic. We prioritize test cricket and with back-to-back Ashes series, we have to be picky and choosy.''
Watson blasted England's bowlers to all corners of the ground, including a 26-run assault on Joe Root all in boundaries off his final over. James Tredwell was also hit out of the attack, England's spinner only bowling four overs.
After Clarke's dismissal for a run-a-ball 75 one of three victims of debutant Chris Jordan England took wickets at regular intervals to restrict Australia to 97 off its last 17 overs. But even a target under 300 proved too much for the hosts.
"I knew how important that game was,'' Watson said. "We haven't had much success so it was nice to have the success we did.
"Things have changed for the better in a big way. We are having a lot of fun. We are playing the brand of cricket we enjoy and everyone is very excited about what lies ahead.''
-AP