How Barcelona performs after the World Cup remains to be seen. Hopefully many of the team have now returned to training. Barcelona have a game in a few days, we will understand if they still have the same performance as before the World Cup.
Espanyol are always difficult opponents, but considering Barcelona and their players are in such good form then of course they are expected to do well too. A number of players involved in the World Cup also played well, but it is unlikely that Barcelona will lose good momentum in the first match after the World Cup break.
I will be very surprised if Barcelona lose to Espanyol. It was a home match for Barcelona, and we know they are currently a very strong team when playing at home. Even Barcelona have not conceded a single goal at home in their last 7 matches this season for Laliga. Barcelona have scored 17 goals in their last 7 home matches in Laliga this season, 6 wins and 1 draw are very good results for them.
Barcelona this season in La Liga really can't be doubted, and even though Espanyol can provide strong resistance when playing against Barcelona based on head to head. But I'm sure Barcelona will still be able to beat Espanyol in this match, because Xavi really seems to have succeeded in shaping Barcelona's performance to be very good in La Liga.
Therefore, I personally really believe that Barcelona will still be consistent in gaining points, especially since Espanyol this season is not looking good.
Usually Espanyol competes in the middle of the La Liga standings, but at this moment Espanyol is only one point different from the team in the relegation zone.
So yes, there is no way for Espanyol to be able to stop Barcelona's run in La Liga, because Barcelona so far at least after being coached by Xavi and then Barcelona can be very good to dominate La Liga again.