Analysis: Four things we learned in Spain's matchday 15

MADRID, Dec. 8 (Xinhua) -- FC Barcelona turned on the style once again, Celta Vigo stunned Real Madrid, and old failings returned to haunt Atletico Madrid. Here are some things we learned this weekend in La Liga.

1. Ferran Torres hat-trick as Barcelona turns on the style

It could have been difficult for Barcelona away to Real Betis, playing against an in-form rival that started the weekend fifth in La Lig