Preview: No rest as Copa del Rey fourth round played in Spain this week

MADRID, Jan. 15 (Xinhua) -- The fourth round of the Copa del Rey knockout competition swings into action this week, with 16 teams looking to qualify for the quarterfinals in a non-stop January marathon of football.

Although the ties between Atletico and Real Madrid, which sees them replay last Wednesday's Supercup semifinal, and Barca's awkward visit to third level Unionistas de Salamanca are not until Thursday,