And Arsenal thought that beating Watford was difficult. Tonight the Highbury club's aspirations to be regarded as one of Europe's elite will be subjected to a full and frank examination by possibly the best club side on the continent.
A win in front of 106,000 people at the Nou Camp is little more than a dream. A point would count as a victory against a team that bristles with the highest quality and, after winning the Spanish title last season, has the Champions League firmly in its heavily bankrolled sights. In fact a win tonight would put Barcelona five points clear in Group B.
This game represents the biggest test so far of Arsene Wenger's studious construction of an Arsenal squad that blazed to the Double in England two seasons ago but, despite reinforcements, has yet to set Europe alight.
Last week's injury-time victory at home to AIK Solna followed an opening performance at Fiorentina that displayed the maturity needed to live at this level, except in the crucial area of finishing, a goalless draw contrasting starkly with Barcelona's subsequent 4-2 defeat of the Italians last week.
Barcelona are built to attack; their formation features a sparkling forward line of Luis Figo, Patrick Kluivert and Rivaldo. The team knocked another four goals past Real Betis on Sunday and promises to add a few more grey hairs to the heads of the Arsenal back line tonight.
But the two goals that Fiorentina scored give Arsenal some cause for optimism. "They score a lot but they concede as well," says Wenger. "If they have a weakness it is at the back. That is why we must have a go at them."
Wenger's plan to try and make attack the best form of defence is dictated also, he feels, by the dangers inherent in Barcelona's passing game. "The quality of their individual technique and passing ability linked to a huge pitch means they pass, and pass, and pass very accurately and wide, and if you run after them they will slowly kill you.
"So we must fight to get the ball and the way we do that will be as important as how we use the ball."
Wenger's admiration for Barcelona's players extends to having at various times tried to buy at least three of them - Kluivert and the De Boer twins, Frank and Ronald - before Barcelona's wallet proved more persuasive.
In fact the squad assembled by the Spanish champions' coach Louis van Gaal includes eight players from his former club, Ajax. Locals have christened the team Barcajax.
Marc Overmars and Nwankwo Kanu also played under Van Gaal at Ajax - in the side that won the 1995 European Cup. So they know the threat posed by the man Overmars calls "a genius". And though Dennis Bergkamp played at Ajax before Van Gaal arrived, the coach knows all about the non-flying Dutchman.
"Our Dutch players and coach feel he is the major threat," says Rivaldo. "Give him space and he will destroy you. That is why he will be tightly marked and given little time on the ball."
Arsenal hope that will leave space for the former Real Madrid striker Davor Suker to embellish his record of seven goals in 12 matches against Barcelona.
Arsenal's only doubts concern Alex Manninger's hand injury; David Seaman, though not fully match fit, stands by. Wenger must also decide whether to play Ray Parlour, back from suspension, or Fredrik Ljungberg wide right.
Meanwhile, Overmars said last night that Arsenal are not afraid of anybody, not even the mighty Barcelona. "We are a team now who work for each other and with that you can achieve anything if the quality is there.
"We have to admit our adventures in Europe the last two seasons look stupid but we know the reason. We were never at 100 per cent because often Dennis Bergkamp could not play and on other occasions I was missing, too. . . To do well in the Champions League and also go for another Premiership title you have to be 100 per cent. And I am convinced we are again now."
