Arsenal match-winner Eduardo scored twice on his first appearance for almost a year and then hailed his achievement as "the best day of my life".
The Croatia forward has been out since February last year following an horrendous leg break but proved his fitness on international duty in midweek.
That convinced manager Arsene Wenger to hand him a recall in place of Robin van Persie for last night's FA Cup fourth-round replay against Cardiff, and the Frenchman was rewarded with a fine first-half effort and a second-half penalty which Eduardo 'won' and converted.
Nicklas Bendtner and Van Persie also got on the scoresheet as Cardiff were comprehensively outclassed. But the night belonged to Eduardo, whose return was greeted with gusto by the Emirates faithful.
"It was the best day of my life," he said.
"It was a special moment to score, very emotional. I celebrated by kissing my wedding ring - because my wife and daughter and family supported me right through this."
Wenger, meanwhile, paid tribute to the striker's reserves of mental strength.
"Everybody is very happy for him. This is the kind of game we love to play, and it was good to see them play with the handbrake off," he said.
"He played a big part in that, and I'm very pleased for him.
"He's been extremely strong mentally. I've never seen one minute of doubt in his mind, not one minute where he said 'I don't want to do this'.
"He is always wanting more. This guy is small but he has the mental strength of a mountain."
The night was not without its worries - Eduardo came off with a slight hamstring complaint - but Wenger insisted he could yet prove crucial to the Gunners' season.
"He had a slight tightness of the hamstring, but we expect it will be a small thing.
"We'll know at the end of the season how important it [his comeback] is, but I'm very happy to have him back. He can play as a striker, on the flank, behind the striker, up front on his own. That is important for us."
Despite leaking four goals, Bluebirds goalkeeper Tom Heaton - on loan from Arsenal's Barclays Premier League rivals Manchester United - put in a fine display.
He made a stunning double save from Carlos Vela and Nicklas Bendtner - both from virtually point-blank range - but was in top form throughout to ensure Cardiff did not go home on the end of an embarrassing scoreline.
Boss Dave Jones said: "All I can take from tonight is that Tom played very well. If it wasn't for him it could have been a cricket score.
"I'm glad the game is over, because we didn't do ourselves justice tonight whatsoever.
"Sometimes when you come to an Arsenal or one of the big clubs you just have to suffer for 90 minutes - and tonight I think we suffered for 90 minutes. I don't think we did ourselves any justice.
"If I could have substituted 10 of them I would have, because we just didn't perform."