When a team has players such as Iniesta, Xavi, Garcia, David Villa, you can play tiki-taka and more, but it was a unique historical moment when initially the Spanish team assembled in 2008-2012 the strongest composition, to compete with which no team was able to.
Then also Barcelona, using the main backbone of the Spanish national team players Iniesta, Xavi, Puyol, Busquets built a team around them, adding the genius of Leo Messi. And we got a tiki-taka, then when these players of the Spanish team were no longer so good, this tactic "fell apart", because it was based on the unique skill of individual players and their chemistry within the team.
Both Barcelona and Spain had golden teams in those years and more important they have perfect tactic tiki-taka which helped both Barcelona and Spain dominated football in Champions League, World Cup and Euro. It is more important because beyond Barcelona players, Spain had good players from Real Madrid that make them stronger.
Later after many months and years, other coaches, other teams figured out ways to constrain tiki-taka. The domination of Barcelona and Spain started to decrease. Next their players from golden era became older and young players can not replaced them entirely. At the end, Barcelona and Spain lost their domination.
the match between barcelona and manchester united is indeed a big match that is quite interesting to the attention of football lovers because these two teams are both trained by coaches who have good quality and also their squad is inhabited by high quality players. So you can say that Manchester United and Barcelona have a pretty strong advantage in their squad
It is interesting because both of them want to win titles as a start to send their crises. They are in rebuilding time and a trophy means a lot for their process. Players will be more interested in joining a winning team rather than a failed team.
Both Barcelona and Manchester United are failed teams in the past several seasons and they need to change it in this season.