The last coach to beat Barcelona at the Nou Camp was Esteban Vigo of Hercules. Asked recently for his plan for shutting down the most prolific team in football, he touched on the question of man-marking Lionel Messi. "There is no point," he said. "You man-mark Messi, then you have to man-mark Xavi, and Villa and Iniesta and Pedro... and then Alves scores."
A killer pass, pulled back from the byline, is actually more likely than a goal from the Brazilian full-back but Vigo is right about Barcelona's No 2 and his incredible influence on the way his team break the opposition down.
Sides that are not undone by the intricate passing of Xavi, Andres Iniesta or the lethal finishing of Messi, Pedro and David Villa – who have scored 82 goals in all competitions this season – will probably be opened up by Daniel Alves.
No defender has a higher assist rate in European football but it is his rather confused status at the club that has muddied the waters of his contract renewal. Barça want him in the same earnings bracket as their top defenders but the player wants to be recognised in the same way as the team's creative attackers such as Xavi and Iniesta. Manchester City will whisk him away at the end of the season if he refuses to sign what is on the table – an offer that the club are not interested in improving.
Chelsea's need for a right-back could also put them in the hunt if Roman Abramovich spends big again in the pre-season. "I can't imagine Alves without Barcelona," said the player last week. But more worryingly for Barcelona fans, he added: "I want to carry on at Barça, but I'm not sure everyone here wants me to."
The stalemate shows no signs of being broken. The club have offered him ¤6 million (£5.1m) a year – parity with World Cup winners Gerard Pique and Carles Puyol – in a deal that would run until 2015. The Arsenal test is another opportunity to show why he believes he is worth more than those two defenders.
On Tuesday he will once again spend more time in the opposition's half than in his own as Barcelona go chasing the game. It will create a problem for Arsenal defensively but it might just give them an advantage.
Late in games, Alves's sprints back towards his own goal are slower than his forward raids. When Andrei Arshavin lashed Samir Nasri's pass into the net to win the first leg for Arsenal, Alves could be seen trotting back, still yards from the Russian when he scored. Arsène Wenger will hope for more of the same on Tuesday.
Arsenal in the Champions' League
1998-99 Group stage
1999-00 Group stage
2000-01 Quarter-final (lost to Valencia)
2001-02 Second phase
2002-03 Second phase
2003-04 Quarter-final (lost to Chelsea)
2004-05 Knockout round (lost to Bayern Munich)
2005-06 Runners-up (lost to Barcelona)
2006-07 Knockout round (lost to PSV)
2007-08 Quarter-final (lost to Liverpool)
2008-09 Semi-final (lost to Manchester Utd)
2009-10 Quarter-final (lost to Barcelona)
Home P68 W44 D16 L8 F137 A52
Away P67 W23 D18 L26 F80 A79
Neutral P1 W0 D0 L1 F1 A2
Total P136 W67 D34 L35 F218 A133