I'd look to real life for this answer. You have 2 sides to this, Barcelona just outplay(ish) Arsenal, so over a few seasons with a similar team each year you will grow the bonds and understanding between your players, a bit like what Wenger instils in his Arsenal team.
On the other hand you have teams that played the opposite, they slow the game down, pass the ball around deep, tire Arsenal and annoy them, effectively sucking the game out of them, then at periods where they concede a lot hit them with an intensive period. I have a save game running where I am Leeds, in 4th season, 2nd in Prem and I decided to try something new against Arsenal, I had 1 Attacking mentality player (AM) and 2 Defensive (CBs) the rest on support, short passing with an equally divided mix of stand off and pressing. The 5 minutes at the start and the end of each half I changed the formation (from 5-3-1-1 to 3-4-1-2) and team mentality from contain to counter...
The result, for the 1st time in 4 seasons, on our 6th meeting Leeds won 4-1 away. Glorious feeling.
Then I got cockey for the home game, didn't use the above and lost 3-0, thus sending me into a 3 month free-fall.