LONDON // Anything following on the heels of "Arsenal 2, Barcelona 1" is a classic let-down. Whether it turns into a classic FA Cup shock hinges on how Arsenal handle the comedown from a glorious Champions League night on Wednesday.
After beating mighty Barca at their Emirates Stadium in London's north, Arsenal move to the rough end of the city's east and to the humble home of the League One side Leyton Orient, who play at Brisbane Road, capacity 9,271.
Although the ground is less than a mile from the awe-inspiring site of London's 2012 Olympic Stadium, it has more in common with the grass-roots pitches round the corner at the famed Hackney Marshes, where hundreds of teams play in various amateur leagues every Sunday.
Long before the days of professional youth academies, the 60-or-so pitches on the grassy oasis amid factories (all now closed) and working-class housing were where many young footballers from that side of London were spotted by scouts.
Orient, who have always suffered in terms of support, being squashed among West Ham United, Tottenham Hotspur and Arsenal, are a club with a proud if not prolific history.
Founded in 1881, Orient are five years older than Arsenal. Of all the London clubs, only Fulham are older. But just once, in the early 1960s, have Orient played a season in the top flight, and they have never won a major trophy.
The closest they came to being in touching distance of silverware was in 1978, when they reached the FA Cup semi-final - only to be swatted aside 3-0 by today's opponents, Arsenal, who went on to lose to Ipswich Town.
Orient epitomise the old Olympian virtue of sport being more about the taking part than the winning, though they are unbeaten this year and are 10th in League One.
As their most famous fan, the composer Andrew Lloyd Webber, said: "I'd just tell the team what I tell all my actors - go out and enjoy it. It doesn't really matter if you win or lose this one. Just savour the grand occasion."
It is a long time since Arsenal have been victims of "giant-killing". Indeed, in the 25 cup ties against opposition from lower divisions under manager Arsene Wenger, the Gunners have never lost.
"We are in all four competitions and it has to be our intention to go in and play hard in all of them. We want to win them all, said Wenger, insisting he will not rest too many of his first-choice team.
"We certainly do not choose to drop any competition; that would be silly. Leyton Orient will be much different to Barcelona, but the commitment will have to be the same."
4.30pm, Aljazeera Sport +3 & +5