Millwall, who are struggling in the Championship this season, have already eliminated Premier League opposition in Everton during their cup run, and it is only Brighton who stand between them and a cup semi-final at Wembley.

"Being a manager or a coach is the next best thing (to being a player)," Harris said. "I don't often miss the games themselves, but there's always one or two a year where you feel 'I'd love to be playing' and Sunday will be one of those occasions.

"(The FA Cup) brings out the best of our principles. In the way we play, what the club's ethos is and what we stand for; certainly being the underdog helps a lot.

"The style of play we've adopted suits cup football, and we have a rich recent tradition in this competition. The amount of Wembley appearances we've had in a short space – it's been a good time for us.

"The players have enjoyed it; taking the focus away from the league has helped us.

"Brighton will come here in good spirits, but everything before the game goes out of the window. The majority of that squad won't have played at The Den – the atmosphere they're going to have on Sunday. When you're looking for things to give you a leveller between leagues, then Sunday's will certainly help us."

Brighton have eased their relegation fears after successive victories in the Premier League, having previously been winless in the league in 2019,  providing Millwall with a greater challenge to overcome.

"Chris (Hughton, Brighton's manager) has done a brilliant job," Harris added. "Any club that gets promoted out of the Championship nowadays and sustains Premier League football; that's a wonderful job. They've put a good squad together.

"It's a big opportunity for both clubs, a great opportunity for Brighton to progress. There'll be expectations they get through against a Championship side and reach a semi-final at Wembley.

"The game being Sunday, the extra day's rest (after Millwall played on Wednesday) certainly helps. But games like this are all about adrenaline, heart; the atmosphere will certainly help."

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