One doesn't exclude the other. We wouldn't have won the league without Messi, but neither would we without a defense and a keeper that has kept this many clean sheets and only conceded 19 goals. We wouldn't have won the league without Mathieus 0-1 header over Celta and his first goal over Madrid either. It's a team effort, but overall Messi is obviously one of the most crucial and decisive pieces, he is the greatest of all time after all. Still, it's a team effort. The Chicago Bulls wouldn't have won their titles without Jordan, but neither would they without the contributions of every other player either.
They are all a piece of the puzzle, and this just goes to show that you don't need a team of "galacticos" to win. What you need is a team - a complete unit of people who work together to become something greater than the sum of its parts. As [MENTION=6099]JamDav1982[/MENTION] says, Masch has been one of the most important pieces of the puzzle that is Barca for years now. He always gives it his all and never complains, being consistently excellent, and that's the reason we all love him so much.