Eduardo's remarkable comeback may just be the inspirational catalyst that finally sparks Arsenal's campaign into life after an emotional evening at Emirates Stadium.

The Croatian's return instigated the home side's most fluent performance for weeks and created a feeling of optimism this part of north London has rarely felt this season.

Although a 4-0 victory against a hugely disappointing Championship opponent is hardly cause for an open-top bus parade, the impact of one of Arsenal's long-term absentees ignites hope that others on the sicklist can emulate his attitude and enthusiasm.

It is a much-cited maxim in football that players need time to readjust after returning from an extended period out but the horrific circumstances of the 25-year-old's double leg-break at Birmingham last February added a psychological question: would he have the confidence in his body and mind to express himself again so soon?

After a bright start, that question was emphatically answered with 14 minutes on the clock when Eduardo attempted to beat Cardiff goalkeeper Tom Heaton from inside the centre circle with an impudent moment of improvisation.

That his effort sailed wide was irrelevant. What it revealed was an admirable and astonishing self-belief that he could simply pick up where he left off.

“I am not surprised he played well,” said manager Arsene Wenger. “I didn't play him as a reward for his excellent work. It was because in training over the past few weeks he has done extremely well.

“He made a big step forward two weeks ago when he found sharpness in front of goal and in his runs and he got rid of his apprehension in the tackles.

“Of course it is nearly 12 months out and he has been extremely strong mentally during that time, I could never see one minute of doubt in his mind or one minute where he said no, I don't want to do it'. This guy is small but has the mental strength of a mountain.”

Thanks in no small part to a Cardiff side who paid far too much respect to their hosts — unlike an idiotic section of visiting fans who threw objects including a shoe and a mobile phone onto the pitch — Arsenal slipped into gear from the off and Heaton had already made a number of notable saves when Eduardo fulfilled any scriptwriter's dream.

With 30 minutes played, he laid the ball out to the left flank where Kieran Gibbs stood up an inviting ball for the comeback kid to head past Heaton from eight yards out with all the assurance of a player who had never been away.

Eduardo's first goal since February 2008 at Manchester City was no more than the Gunners' slick passing deserved and when Nicklas Bendtner rose above two defenders to steer home a Samir Nasri corner, only the margin of victory remained in doubt.

A soft penalty allowed Eduardo to stroke home a third before a slight hamstring problem prompted his 67th minute withdrawal to a standing ovation.

Wenger said: “We will know how important this was at the end of the season. I am very happy to have him back because he gives us options.

“We will see how he responds to that hamstring and maybe he can be with us on Saturday.”

It was poignant that Robin van Persie, who has so often been wrapped in cotton wool for less high-profile matches such as this, replaced Eduardo and as if to provide a reminder of the Dutchman's quality, he smashed home a late fourth to give the scoreline the thoroughly one-sided slant it deserved.

“It was a good team performance; dynamic, convincing and mobile,” said Wenger. “We played the kind of football we love to play and it is good to see us play with the handbrake off.

“We are now consistent, we are stable defensively and we added our drive going forward.”

Indeed, it was difficult not to get caught up in the optimism swirling through the stadium when considering the players Arsenal can welcome back in the coming weeks.

Should captain Cesc Fabregas, Theo Walcott and Tomas Rosicky return from injury on schedule, Wenger will suddenly have a flood of options in attacking areas with any immediate dividends from new signing Andrey Arshavin a welcome bonus.

Eduardo's sparkling reintroduction will also have Emmanuel Adebayor looking over his shoulder.

The Togo forward has failed to hit the heights of last season's 30-goal heroics and will need to raise his game or risk finding himself fighting for his place with all the momentum seemingly lying with the Croatian.

Of course, Arsenal must now reproduce this kind of display in the tougher challenges that lie ahead and Wenger said: “We missed the goals recently but I believe we are on a very strong run.

“We promised ourselves we would give everything until the last day of the season. Our basic target is to get in the Champions League which means the League is our priority.”

But if the remainder of Arsenal's star-studded injury victims follow Eduardo's example, Wenger could be right in thinking his young Guns were written off as trophy no-hopers a little too soon.