Portugal appointed Racing Santander coach
Portugal, 53, returns to a club he coached in the 2006-2007 season leading them to a 10th-placed finish.
His first game in charge is at the Bernabeu on Saturday against Real Madrid. Portugal was previously Real's youth team coach and was technical secretary there from 2007 until last June.
Racing sacked Juan Carlos Mandia just over a week ago with the club 17th in La Liga having only one league win to their name this season.