The Argentine attacker stated earlier this week that the tactician\'s presence at the club is more vital than his own, but the Spain international feels there is no need to choose between the two as they are both key to the Camp Nou outfit in different roles. \"Both Guardiola and Messi are essential. Why pick between the two if they could both still be at Barca for many more years,\" Xavi told reporters at a promotional event. \"Guardiola has given us a lot as a coach, both to the club and the players, while it\'s Messi who makes the difference on the pitch.\" Messi has been in superb form for Barcelona in the 2011-12 campaign, and has already netted 50 times in official games.