Swansea losing the UK City of Culture 2017 bid to Hull is a "bitter disappointment", the city's council leader has said.
David Phillips told BBC news there was nothing wrong with Swansea's bid and said they would not let the good ideas "slip through their fingers".
In an apparent swipe at the winners, he said people who lived in Hull "had to have something to look forward to".
UK Culture Secretary Maria Miller announced the winner early on Wednesday morning.
Mr Phillips told BBC Radio Wales after the announcement: "We congratulate Hull, but I'm disappointed not least because hundreds of thousands of people supported the bid.
"When we went in to make our presentation we knew there were six people in the room, but we knew there were hundreds of thousands of people urging us on.
"I want to tell them don't be down-hearted, this is just the start - we won't give up.
"There were too many good ideas in the bid, we're not going to let them slip through our fingers.
"I don't think there was anything wrong with the bid. Clearly Hull's was stronger than ours.
He added: "If you live in Hull, you've got to have something to look forward to I suppose."
Welsh Secretary David Jones MP called the campaign inspiring, adding the city should capitalise on "the passion and commitment" it had roused.
He said: "As much as today's announcement will come as disappointing news to those who have supported Swansea Bay's bid, they should be rightly proud of all that they have achieved.
"The 'Cwtch the Bid' campaign was an inspiring effort that spread beyond a city and a region; it was an effort that galvanised the support and imaginations of people all across the country.
Actor Michael Sheen, ex-Doctor Who producer Russell T Davies and singer Bonnie Tyler had backed the bid.
"It's a disappointment of course, but it will make us try even harder for next time - it'll happen," he told BBC Radio Wales.
Ms Miller said she hoped the losing cities would "take forward many of the fantastic ideas and events they had planned so that their communities can enjoy these innovative cultural plans".
It had been estimated winning would have been worth about £70m to the Swansea Bay economy, with hotels, restaurants, shops and other businesses all cashing-in from the events programme and hundreds of thousands of visitors.
Swansea Bay boasts key cultural figures from every generation but poet Dylan Thomas is the most famous of them all.
Other famous cultural figures from the Swansea Bay region include Hollywood stars Richard Burton, Sir Anthony Hopkins and Catherine Zeta Jones, and comedian Rob Brydon.
Along with Sheen, composer Karl Jenkins, singer Tyler and comedian Rhod Gilbert had backed Swansea Bay's bid.
"Culture for us here in Swansea Bay is the ordinary - it is our way of life, it defines us and we define it," said Sheen.
"But what is ordinary for us here in Swansea Bay I believe is extraordinary for others.
"Our outstanding scenery; our proud industrial past; our cultural assets; our creative, clever resourceful people; our premier sporting achievements - all of these things provide a unique culture which I am extremely proud to be a part of."
The UK government created the title in an attempt to replicate the success of Liverpool as European Capital of Culture in 2008.