La liga barcelona lose madrid win to go top

I think there may be some confusion here!

In La Liga, Barcelona and Real Madrid are two of the biggest rivals, and it's unlikely that Barcelona would lose to Madrid and then go top of the table.

In fact, the opposite is more likely to happen. If Barcelona were to lose to Madrid, it would likely mean that Madrid would go top of the table, not Barcelona.

Could you be thinking of a specific match or season where this happened? I'd be happy to help clarify!