Brendan Rodgers has said conceding two goals at the start of the second half enabled his Swansea team to get their minds back on the game and beat Reading to claim a place in the Premier League.
A brace from Scott Sinclair and a Scott Dobbie strike had put the Welsh outfit 3-0 ahead at half-time, but a headed goal from Noel Hunt and another from Matthew Mills brought Brian McDermott's Royals back into the match.
Sinclair converted a penalty to complete his hat-trick and send Swansea into the top flight for the first time since 1983.
"It was a fantastic game," said former Reading boss Rodgers. "I don't think we played as well as we did for most of the season but on the moments when we did show our quality we were very, very good.
"Conceding two goals helped us refocus and get a bit of control - it's fantastic. The supporters today were incredible and it's nice to repay their faith and get promotion.
"It was a proper, proper game and these players deserve to be in the Premier League. Ourselves (runners-up) Norwich and (champions) QPR will be a credit to the Championship and will try to do well.
"We show courage and try to pass the ball - but the important thing today was to try to win the game. I said to the players it wasn't about winning, it was about defending our principles and how we played. We got a bit nervy but regained our composure and started to pass the ball.''
Sinclair arrived at the Liberty Stadium from Chelsea at the start of the season and the Swans top goalscorer was quick to praise his team-mates and Rodgers.
"I'm buzzing. Credit to the boys - it's fantastic. Brendan deserves massive credit - he's been exceptional and puts all the hard work in every day in training.''
The Swansea players sported T-shirts dedicated to former team-mate Besian Idrizaj as they collected the trophy,the Austrian who died of a heart attack last year.
"He's always in our memories,'' said winger Nathan Dyer, while defender Garry Monk remarked: "It's for Besian.''
Club chairman Huw Jenkins said he was still coming to terms with what the team had achieved.
"Travelling back I think we will have to pinch ourselves to get back to reality," he told Sky Sports. "It's been a remarkable 10 years for this club and to have an opportunity to continue growing and building next year - and playing the very best teams in the country - is fantastic.
"We had our luck today and sometimes in sport you need that but I think it's a great achievement - not too many teams play this way in Britain. We've stuck with it through different managers and we want to continue that path next year. Hopefully that philosophy will continue for a long time.
"Go back two years and we thought we had a massive task when we got into the Championship - so we've got no worries going in and testing ourselves against the best. We'll give it everything we've got.''
McDermott congratulated Swansea on their achievement and said his Reading team could still be proud of their season despite the defeat.
"In February we were 12th or 13th but we've got into the play-offs and beaten Cardiff to come to Wembley. In the first half nothing dropped for us but Swansea played very well. 3-0 down is a mountain to climb but we were inches from getting a third goal.
"Jem Karacan hit the post and if it had gone in I think we'd have gone on to win the game...I honestly believe it would have been a different scoreline. I'm just really disappointed for our fans. I wish we could have got the right result for them."