(CNN) -- When Vincent Tan led a Malaysian takeover of Cardiff City in 2010, the Welsh soccer club was battling crippling debts -- and a long-awaited return to England's top flight was tantalizingly out of reach.
The new owners, frustrated by two more near promotion misses, decided that a major overhaul was necessary.
Along with major investment, the team's historic blue strip was last season changed to red to appeal to Asian supporters and a dragon put on the club crest in prominent place above its iconic bluebird.
However, most supporters were won over when the "Bluebirds" clinched promotion to the Premier League as champions -- and their delight grew on Sunday with a shock victory over one of the richest clubs in the world.
Manchester City traveled to the Welsh capital on the back of a 4-0 thrashing of Newcastle on the opening day of the season, but left smarting after a 3-2 defeat against a side widely tipped for an immediate return to division two.
It was the first time Cardiff had hosted a top-flight match since 1962, and Malky Mackay's team had suffered a 2-0 defeat last weekend at West Ham -- a mid-table side last season.
"This was the first time that we've played at home in the Premier League, and the first time in 51 years that we've been in the top division, so it meant a lot to a lot of people," he told reporters after two goals from former Manchester United striker Fraizer Campbell set up victory.
"I'm very proud of a lot of people at the club; obviously the players but also the fans who made the atmosphere unbelievable today. Also, the people who work at the club, because they've been through some tough times -- to see them with smiles on their faces as I walked through the tunnel lightens my heart.
"Manchester City are one of the top teams in Britain and Europe, and are full of top Premier League talent."
As Manchester City's new manager Manuel Pellegrini commented afterwards: " I did not expect to lose."
City, EPL champions two seasons ago, spent more than £100 million ($155 million) before the start of the season -- bankrolled by the club's oil-rich Abu Dhabi owners.
However, it was Edin Dzeko -- himself a big-money buy during the tenure of previous manager Roberto Mancini -- who put the visitors ahead seven minutes after the break.
But the Bosnia striker's stunning strike was soon canceled out by Cardiff's Iceland captain Aron Gunnarson, and one-cap England international Campbell then twice got the better of his marker Pablo Zabaleta to force home from successive corners.
Substitute Alvaro Negredo, one of Pellegrini's acquisitions, gave the visiting City hope with a debut headed goal of his own in the 90th minute but Cardiff held on.
"Playing against a Manchester City team that only lost one game from a winning position last season, and to come back and show that character today -- I thought we deserved to win the game," Mackay said.
"My players are here on merit -- we proved that today."
Meanwhile, Tottenham became the third team to start with successive victories after beating the EPL's other Welsh club, Swansea, 1-0 on Sunday.
New signing Roberto Soldado scored his fourth goal in three games as the London club joined Chelsea and Liverpool on six points.
The Spain striker scored the only goal from the penalty spot in the second half, as he did against Crystal Palace last weekend before netting twice in the 5-0 Europa League thrashing of Dinamo Tbilisi.
Gareth Bale, Tottenham's top scorer from last season, was given the weekend off due to his apparent injury.
The Wales forward is expected to be unveiled by Real Madrid in a world-record signing next week, but Spurs manager Andre Villas-Boas said he expected the player to be at training on Tuesday.
"There is interest from Real Madrid. Whether the transfer will happen or not, hopefully you will have more news in the next couple of days but at the moment there is nothing I can tell you," he added.
"Tomorrow is a day off. Tuesday is training so I would expect him to be there."
Villas-Boas wryly shrugged off Chelsea's Sunday announcement that the club had hijacked Tottenham's bid to sign Brazil forward Willian from Russian team Anzhi Makhachkala but confirmed that Steaua Bucharest defender Vlad Chiriches is set to join Spurs.
"Maybe someone will steal him as well," Villas-Boas joked.
Chelsea, meanwhile,will face a big test of the club's title ambition under Villas-Boas' former mentor Jose Mourinho in Monday's clash with EPL champions Manchester United.