Preview: La Liga giants at stake in Copa del Rey second round

MADRID, Dec. 13 (Xinhua) -- Several La Liga sides are in danger of being the victims of a Copa del Rey upset in the second round of Spain's knockout tournament this week.

Although the first round matches, which saw La Liga teams play rivals from the fifth and sixth tiers, didn't produce any upsets (although Rayo Vallecano needed a penalty shootout against fifth-tier side Guijuelo), the second round sees sides fr