England's coach and captain are convinced it was a lack of experience that cost their tourists in series defeat against South Africa.
Eoin Morgan's team led 2-0 six days ago, yet ended up 3-2 losers after a five-wicket defeat in the deciding one-day international at Newlands.
AB de Villiers' unbeaten 101, his 24th ODI hundred in his 200th match, cancelled out Alex Hales' 112 as England lost a third successive match despite an individual century.
There was minimal support for Hales as the tourists were bowled out for 236 in 45 overs.
Then even after Reece Topley had taken three early wickets, De Villiers and Hashim Amla (59) eased South Africa into position to prevail with six overs to spare.
Bayliss conceded England had not come up with their best cricket when it was needed.
He said: "We've certainly got some work to do there, and that will come with experience.
"At some point, that experience has got to pay dividends. I hope playing against someone like De Villiers and the way he went about the innings today is something we can learn from and that will rub off."
This is just the third time any team has hit back from 2-0 down to win a five-match series, and Bayliss believes his young team will become more consistent with maturity.
"I think to win series, we've got to take a leaf out of De Villiers' book, the way he paced his innings," he said.
"The best batter in the series did his job today, and showed everyone how to do it.
"I think the consistency of performance will come with experience, but sooner or later guys have to be accountable."
Morgan told a similar tale as he came to terms with defeat, less than a week after England had been talking publicly about inflicting a 5-0 whitewash on their hosts.
"I don't think we did enough - we were outplayed here today," said the captain.
"We did have chances in previous games to wrap up the series, but we weren't good enough.
"The opportunities would have been executed if we had more experience in the side, but we're growing and learning.
"We pushed them so hard, even though we under-performed.
"We started with the ball exceptionally well, but it just wasn't enough."
De Villiers was proud of South Africa's resilience, but had praise for England too.
He said of the opposition: "They're a fantastic one-day team.
"To come back from rock-bottom, in the 2015 World Cup, to where they are now ... the talent was always there, but mentally they had to go through a few obstacles.
"'Morgs' played a big role in that. He's a very positive leader ... and he's the right captain for England.
"They will be a team to deal with over the next few years. In the 2017 Champions Trophy, 2019 World Cup, they'll be around - there's no doubt about that."
Asked what ultimately decided the outcome in a hard-fought series, he added: "I think the difference was probably hunger.
"We were just maybe a bit more hungry than England to really nail it down - to come back from 2-0 down is something really special.
"We had to come back from a very, very difficult position, but we didn't lose the belief ... even though we were in a really dark place.
"We had something nice going at SuperSport Park (in the fourth ODI), and that's where things turned around for us."
Bayliss identified England's fielding as their most obvious weakness.
Adil Rashid dropped a crucial catch in the penultimate match, and the coach said: "I thought the batting and bowling was fairly even. They are quite simply a better fielding team than us at the moment and we've got to keep working at that.
"We've got a number of guys who are not the quickest in the field but I think it's an attitude thing.
"I just feel at times that some of us don't necessarily want the ball to come anywhere near us.
"That's something we're working on, and will continue to work on."