Captain Alastair Cook was left bemused by David Warner's controversial television recall for a catch behind after England lost the first one-day international against Australia by six wickets.

Aaron Finch's second ODI century condemned England to yet another defeat on a miserable tour after he combined in a record 163-run opening stand with Warner (65).

England believed, however, that they had removed the left-hander on 22 when he walked after wicketkeeper Jos Buttler claimed a low catch.

The standing officials opted to review it and when the replays were not quite as clear-cut, TV official Kumar Dharmasena recalled Warner, who had almost reached the boundary's edge.

Cook was certain the wrong decision had been made.

"It might be my English eyes on it but I thought it was a pretty clean catch," he said.

"It hit his fingers and bounced up. I only saw it a couple of times on the big screen and I thought it was the wrong decision.

"Obviously David thought it has carried because he was quite happy to walk off.

"It is strange because a lot of those catches look a lot worse on TV than they do in real life. That one I didn't see it hit the ground.

"We have to respect the umpire's decision."

Asked if it was a key moment, Cook added: "I think they were on around 80 so they had made a good start. They still needed 200."

England, who left out Hampshire pair Michael Carberry and Danny Briggs, perhaps provided too many errors of their own to pin defeat on that one moment.

Sloppy fielding, which most significantly saw Gary Ballance drop Finch on eight, and a painfully slow start in comparison to Australia stood out as obvious concerns.

Cook's own form is, however, top of his list of worries after he failed to last the opening over before edging behind off Clint McKay.

The 29-year-old had already survived a strong shout for lbw from the first delivery of the day, and his problems were put into context when his opposite opening rival Finch won the game with his 121 from 128 balls.

"I need to start scoring runs to help us start turning games around," he said.

"I can't keep asking the lads to do it if you're not doing it.

"I need a little bit of luck to get me going, but the way I hit the ball in practice (this morning), I know it's only practice and it counts for b***** all, but it was as good as I have hit the ball all tour."

Cook conceded the fielding performances - which have marked England's decline this winter - were now too frequently costing his side.

The impressive Chris Jordan could have removed both Finch and Warner before they reached double figures, only for catches to go down.

Ballance, who earlier hit 79 in a total of 269 for seven, would have felt he should have held on when he got two hands to a fierce Finch drive.

"The couple of dropped chances when you are defending 270 against a good side, you need to take every chance you get," Cook said.

"It is something we are aware of. We haven't fielded to the standard that we're capable of on this tour.

"We're not bad fielders, it is just in the last three or four months - it's probably actually been longer than that - we've been dropping too many chances.

"We can't keep gifting quite simple chances away because you get punished in international cricket."

England will head to Canberra for a tour match against a Prime Minister's XI on Tuesday and, while that would appear a low-key affair, any sort of victory now would be welcomed to try to boost flagging morale.

"It's tough when you keep losing games of cricket to keep confidence up," Cook said.

"You can keep preparing the right way and talking the right way, but it does take a hit when you keep losing games of cricket.

"We just need to somehow stop the rot. It's amazing then how quickly it can turn around.

"There's no better place than getting some good preparation on Tuesday and then coming out on Friday (for the second ODI in Brisbane)."

Finch, who scored 156 for Australia in their t20 win against England at Hampshire’s Ageas Bowl last summer, denied that he thought England were now ready for the taking following their latest loss.

Cook's side began the series third in the International Cricket Council's ODI rankings, just behind Australia, and the opener expects the five-match series will be run close.

"They're a quality one-day side and we saw even if they lost a couple of wickets up front they were still able to get 270 and attack quite hard at the back end," he said.

"They are third in the rankings - you don't get to that level by not being good. They are an outstanding side.

"To start the series so well, with the bat especially, was nice to continue the momentum that the Test side have created."