After the final whistle blew here and Millwall's players walked across the pitch in triumph, a TV camera caught the visitors' right-back, Alan Dunne, pushing his team-mate, and the game's outstanding performer, James Henry towards a police dog. It was a smirk-inducing moment but equally revealed a deeper burst of emotion on the part of the perpetrator.

Dunne is the only Millwall player who was part of the squad that participated in the 2004 FA Cup final. As the club booked their place in the competition's sixth round for the first time since that campaign, the 30-year-old could not help but reflect on the frustration he still harbours at not playing in that match, which Millwall lost 3-0 to Manchester United at the Millennium Stadium, and the excitement he now feels at being just two wins away from getting a chance to participate in the showpiece again.

"It would be lovely to get into the final, and this time I'd love to be involved. That would make up for Cardiff," said Dunne. "I was in the starting line-up until two nights before the game but Wisey [Dennis Wise, Millwall's then player-manager] said he was going to play.

"I was heartbroken but he told me he was only going to last 50 minutes and I would come on. So after half-time I started warming up but ended up spending the whole half running up and down the touchline. It was tough to take."

Dunne is entitled to dream of getting another shot at an FA Cup final, although the player will be aware that should Millwall make it to Wembley (which they would also do by making the semi-finals) he could yet again find himself on the bench given his usual role as understudy to Adam Smith, the talented 21-year-old who joined on loan from Tottenham in November and has established himself as the first-choice right-back.

Indeed it was a surprise to see Dunne selected over Smith for the trip to Luton. But having made his 14th appearance of the season the Irishman, who joined Millwall at the age of eight, could now take some shifting. He was part of a defence that was without the injured captain Danny Shittu but stood up admirably to sustained pressure and provided a platform for those further up the field to score the goals which saw them progress through this fifth-round tie.

Henry scored the first on 12 minutes after capitalising on poor defending from Janos Kovacs before the winger then provided the cross for Rob Hulse to double the visitors' lead with an exquisite volley. The substitute Dany N'Guessan completed the victory with a close-range finish late on.

Next up for Millwall is Tuesday'svisit of Peterborough and the opportunity to put their pursuit of a Championship play-off place back on track. But there is no denying the excitement which another FA Cup run has brought to this corner of the capital, with Kenny Jackett's men drawn to face Blackburn Rovers at home in the next round.

"It's great to be in the last eight and being this close you start to dream," said Jackett. "Playing Manchester United in the final again would be fantastic."

Luton's focus is solely on making the Blue Square Bet Premier play-offs and putting to the back of their minds a Cup run in which they became the first non-league side in 24 years to knock out top-flight opposition when they beat Norwich City in the fourth round.

This encounter ultimately proved a step too far, although there was relief to be had for everyone associated with Luton that a match which had the potential for trouble resulted in only seven people being arrested for public-order offences.

"The Cup run shows we've got a very good side, but there's still an awful lot of work to be done," said Paul Buckle, the Luton manager. "Nobody should underestimate the job of getting Luton into the Football League. Every time we play, it's a cup final for the opposition. That's something we have to get to grips with."

Man of the match James Henry (Millwall)