Malky Mackay backed Fraizer Campbell to force his way into the England squad after the striker grabbed two goals in Cardiff's stunning 3-2 win over Manchester City.
Few had given the Welsh club a chance of pulling off an upset in their first Premier League home game, and they fell behind to Edin Dzeko's fierce strike early in the second half.
But they hit back as Aron Gunnarsson tapped in from close range before Campbell twice lost Pablo Zabaleta from corners to head home and spark scenes of delirium at Cardiff City Stadium.
Alvaro Negredo got a goal back for City in stoppage time and spurned a last-gasp chance for an equaliser, but it was not enough as manager Manuel Pellegrini was given a rude awakening after their handsome opening win over Newcastle.
Campbell's career has been heavily affected by injuries since he made his breakthrough at Manchester United, but his pace constantly troubled Joleon Lescott and his stand-in defensive partner, Javi Garcia.
And manager Mackay believes performances of this quality mean he could soon be adding to his solitary England cap.
He said: “I thought Fraizer Campbell gave their whole back four problems today. He is someone I was delighted to get when we managed to get him in from Sunderland for £600,000. I thought it was an incredible bit of business on our behalf, and he hit the ground running.
“He needed to get fit and he needed to get sharper and he needed to regain belief in his own ability, and that is what we gave him.
“He worked hard over the summer, and I now think I have a player there who has had an England cap and, over the piece, I think could force his way back into that squad if he keeps his head down and keeps working and playing like that against top, top players.”
Mackay also praised the raucous support his side received from the 27,000-strong crowd as they claimed one of the most famous wins in the club's history.
“When the goals went in it was something quite incredible,” he said. “The stadium, the team, the staff and the fans did us proud today in front of a worldwide audience. The passion the people have got for this showed when the goals went in.
“It is something that is going to be massively important for us going forward. They are our 12th man.”
Despite watching his side concede two goals at set-pieces, Pellegrini refused to single out any of his defenders or keeper Joe Hart, who hesitated when deciding whether to come for the ball for the first of Campbell's brace.
He said: “Defending set-pieces is the duty of all the team, not just the goalkeepers and the defenders. It does not matter who is guilty with the two corners, conceding from two corners is too much, it is too important an area.
“When we scored the first goal I thought it would be easier for us as we were playing a team defending with ten players inside their box. It was very difficult for us and I think, while we did not do a very good match, we did not play badly.
“We had the patience to try and score, we did it but it was a pity with the two corners.”
Information from the Press Association was used in this report.