Barcelona are a team full of superstars; they have the illustrious trident of Neymar, Luis Suarez and Lionel Messi up-front and the commanding figure of Gerard Pique at centre-back.
But which player in particular makes the difference for the Catalan giants? Surprisingly, it's not Lionel Messi or Andres Iniesta - it's last summer's signing from Lyon, SamuelUmtiti.
The 23-year-old central defender was absent at the weekend, having played in the 6-1 midweek victory over PSG, and Barca boss Luis Enrqiue certainly missed his powerful defender as they lost 2-1 to Deportivo La Coruna.
Umtiti has played in 16 La Liga games so far this season, every single one of which have been victories, not even one draw or defeat.
Barcelona in #LaLiga this season:
With Samuel Umtiti: WWWWWWWWWWWWWWWW
Without Samuel Umtiti: LDWLWDDDDDL
Key to their success. ï‘Š pic.twitter.com/cjrV5hLLiz
Without the Frenchman at the back, Barcelona usually capitulate, picking up just two wins from the 11 games he hasn't played in, six being draws and three being defeats.
Barcelona slipped off top spot in La Liga this weekend having lost at Deportivo - they now sit two points behind Real Madrid who have a game in hand.