Much of the discussion about Arsenal's central defense has come to fruition.

Barcelona forwardLionel Messi broke it down, and scored a goal in the late minutes of the first half. It came on a defensive break down, starting with Cesc Fabregas's ill-conceived back-heel.

Andres Iniesta fed Messi perfectly, and the Argentine delivered as he usually does.

If the score stands, Barcelona will advance on away goals.

Adriano, a surprise start, hit the post in the post in the 35th minute. But aside from the Messi goal, it was a rather uneventful half despite some physical altercations.

After all the speculation circulating around Robin van Persie, the Dutch forward has been almost non-existent, aside from the yellow card he received after retaliating against Barcelona defender Eric Abidal's grabbing at his throat. Goalkeeper Victor Valdes has been untested the entire half, as has the Catalans' makeshift defense.

Arsenal got a bad break, when a ball fired by Dani Alves on a free kick found its way into the hands of Wojciech Szczesny. But the young goalkeeper appeared to hurt his finger, and was substituted out for third-string goalkeeper Manuel Almunia in the 19th minute.

Laurnet Koscielny did some fine defending on Messi in the 12th minute. The French defender also picked up a yellow card in the match.

Bacary Sagna is playing with a yellow, as well.

BARCELONA STARTERS

G: Valdes 1

D: Adriano 21, Abidal 22, Busquets 16, Alves 2

M: Iniesta 8, Mascherano 14, Xavi 6

F: Messi, Villa 7, Pedro 17

BENCH:

G: Pinto 13

D: Milito 18, Maxwell 19

M: Thiago 30, Keita 15, Afelllay 20

F: Krkic 9

ARSENAL STARTERS:

G: Szczesny 53

D: Clichy 22, Koscielney 6, Djourou 20, Sagna3

M: Wilshere 19, Diaby 2, Nasri 8, Fabregas 4, Rosicky 7

F: Van Persie 10 

BENCH:

G: Amunia 1

D: Squillaci 18, Eboue 27

M: Arshavin 23, Denilson 15

F: Bendtner 52, Chamakh 29