The 20-year-old Murray, one of several players fighting for the two remaining tickets to the Nov 11-18 season-finale in Shanghai featuring the world’s top eight, needed just 69 minutes to brush aside the 34-year-old Santoro.
The Scot climbed to a provisional eighth in the ATP Race and could score precious points in the next round when he faces another Masters Cup contender in Frenchman Richard Gasquet, who pleased the home crowd with a 6-4, 6-4 win over American James Blake.
World number two Rafael Nadal advanced in determined fashion with a 6-4, 6-3 win over Swiss Stanislas Wawrinka.
The Spaniard will meet German Tommy Haas or Russia’s Mikhail Youzhny for a place in the semifinals.
Cypriot Marcos Baghdatis had earlier knocked out Paris title-holder Nikolay Davydenko with an impressive 6-2, 6-2 win to keep alive his own Masters Cup hopes.
Baghdatis gave a near faultless display to set up a quarterfinal with Spain’s Tommy Robredo, the eighth seed, who moved past Argentine Guillermo Canas with a 7-5, 7-5 win.
Federer wins
In a late night clash on Wednesday, Ivo Karlovic broke Roger Federer’s serve for the first time in his life, but couldn’t stop the Swiss juggernaut from rolling into the third round. Croatian Karlovic, the tallest man in tennis at a tree-topping 2.08 metres, went down 6-4, 4-6, 6-3.