England play Sri Lanka in the Champions Trophy on 25 September
England captain Andrew Strauss refused to be despondent despite the team's seven-wicket defeat at Lord's that saw Australia secure the one-day series.
"I don't think there's a massive gulf between the sides by any means but one batting unit is a lot more confident than the other," he told BBC Sport.
"The same mistakes are being repeated and that is very frustrating.
"We need to be a bit more pro-active, you have to play with a certain degree of freedom and we need to improve."
England now have three more matches in the series before their first match in the ICC Champions Trophy in South Africa against Sri Lanka on 25 September.
"I wouldn't say that it's a net for the Champions Trophy - I'd say it's a chance for us to salvage something out of this series," Strauss said.
"There is plenty to keep us motivated, the Champions Trophy is just round the corner and that is something we need to get prepared for but more immediately we need to win a couple of these last games.
"For the first two games I though we had great chances of chasing down those scores, the last couple we haven't had enough runs on the board so the Aussies have been able to win at a canter."
In the latest defeat, England collapsed from 96-1 in the 19th over to 220 all out, with Brett Lee in devastating form.
"Brett bowled exceptionally well to take three wickets in that powerplay when we had a bit of a base, not as good as we'd have liked but we were looking at 260-odd but we had probably lost a wicket or two too many at that stage anyway," Strauss admitted.
"We're all to blame and we're the only ones that can change it.
"I don't think we played massively bold strokes by any means, obviously you have to play some bold strokes in the powerplay overs but we found ways of getting out."
Although the series has gone, tickets have all been sold for the remaining matches - two day/night games at Trent Bridge and a finale at Chester-le-Street on 20 September.
"We've got an obligation to put on some entertainments for the crowd and hopefully we'll be able to do that," Strauss said.
Counterpart Ricky Ponting was pleased with his team's performance, but still looked for improvements.
"It was a pretty easy run chase, we got the runs comfortably and we never got out of second gear," he said.
"Early on with our bowling I thought we were a little bit off and let them get too many easy boundaries, but we managed to peg it back through the middle.
"Nathan Hauritz bowled exceptionally well and kept us right in the game and when the ball started to get a bit old and Brett came back on that's where the game changed.
"We've got to make sure we're a little bit better at the top of the innings with the ball but otherwise we've had a very good game.
"You need your bowlers to create pressure and I think when Hauritz came on was when we got hold of the game.
"He has bowled really well to Strauss all the series and we were able to keep reasonably attacking fields, we never really gave them those easy singles that you can get through the middle of one-day games and that's all a result of good bowling.
We have done a lot of things really well through the series
"We have done a lot of things really well through the series, we've had really good batting partnerships when we've needed them and really good bowling partnerships when we've needed them and that's always what you need if you're going to win games of one-day cricket."
Looking ahead to the final three matches, the skipper - who flew home for 10 days after the Ashes defeat - said: "When you're 4-0 up with three games to go it can be a little bit harder to really focus so I'm going to have a talk to the guys and break it down into two series.
"The first one has gone and now I want to make sure we've got a three-game series coming up."
Man-of-the-match Lee was delighted to have such an influential role, having played no part in the Ashes defeat because of injury.
"It's been a tough tour for me but I'm past that but I've been given the opportunity to play one-day cricket for Australia and I'm loving it. This is a special place to play cricket and to take five wickets at Lord's makes it a very special day for me," he said.
"We're very hungry, losing the Ashes hurt us immensely and we're trying to rectify that and can only do that through one-day cricket now.
"The guys have trained very hard, yes it's a different format but we've taken the hurt from the last couple of months and tried to bundle all that energy into the one-day cricket."
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