Barcelona's unbeaten streak continues, Xavi is happy, Barcelona is happy, the fans are happy and everyone is happy (especially the gamblers who bet for Barcelona). Of course Barcelona has higher chance of winning the La Liga title this season if it doesn't make mistakes in the rest of the season. But I think it's still possible for them to drop some points unexpectedly against weaker team or maybe against Real Madrid and derby match, so of course they have to try to avoid those mistakes for the rest of the season.
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Any series ends sooner or later and it would be interesting to "catch" this moment. Let's assume that with a minimum odds of an underdog winning against Barcelona of 4, we have three attempts to guess this moment and be in profit by at least one bet (if the third bet wins). But now there are two obvious matches ahead where Barcelona can lose - against United and against Real, I doubt that the odds of United and Real to win in them will be much more than 2.
Losing points is still very likely to be felt by Barcelona even though they are currently in a very good trend. Talking about this is football, sometimes luck and bad luck will be experienced by a team with their good performance or with their bad performance. What Xavi Hernandez can do is motivate his players to stay focused on the game, be it when facing a strong team or a weak team.