#4 A resolute defense
The defensive line of Barcelona possesses a lot of quality and experience. However, it is sometimes erroneous, and a few mistakes do happen. Many fans and football pundits have questioned the efficiency of Barcelona's defense, but one should not forget that the core was the same when they won the UCL three years back.
Gerard Pique is another war veteran in the team whose towering presence forces opposition strikers to chicken out. On his day, he doesn't let anybody past him with his well timed tackles. He is Barcelona's defender-scorer just like his friend and Real Madrid player Sergio Ramos.
Samuel Umtiti has taken up the reins from Carles Puyol, and he has excelled in the role, even winning the FIFA World Cup with France last summer. Clement Lenglet, a new signing from Sevilla, is a dependable player when it comes to shutting strikers out, and Thomas Vermaelen's experience comes handy in tricky situations.
Jordi Alba is undoubtedly one of best left-backs on the planet, and his combination with Messi is a joy to behold. Sergi Roberto's capability at the right-back position or as a midfielder is very well known as well. Besides that, Nelson Semedo can also deputise in his position whenever the situation demands.