كتب : وكالات
Barcelona keeper Victor Valdes denied Santander a stunning opener in the 25th minute when he superbly dived to block Ezequiel Garay's penalty after Juliano Belletti leant on Juanjo inside the area.
Brazilian playmaker Ronaldinho, who was criticized for poor displays in recent matches, put the hosts ahead six minutes after re-start when he curled a brilliant free-kick that sailed over the wall and into the back of the net.
He ensured the victory seven minutes past the hour mark after he headed home Deco's free-kick from close range.
The victory sent Barcelona three points clear at the top of the league table with 46 points following Sevilla's goalless draw with Real Betis on Saturday.
Elsewhere, Valencia wasted a chance to move back to third place after suffering a 3-0 defeat to Getafe.
Mario Cotelo grabbed the lead for Getafe in the 46th minute before Daniel Güiza extended the gap 12 minutes later.
Midfielder Nacho wrapped up the win in the 79th minute.
Valencia are fourth with 39 points, two behind third-placed Real Madrid who edged past Real Sociedad 2-1.