In dry and sunny conditions, Hamilton's time of 1:14.131 was good enough to stay on top.
Teams concentrated on tyre work as Pirelli's brought their 2013 compound tyres to Brazil to be trialled.
Title contenders Sebastian Vettel and Fernando Alonso were second and fifth respectively. Vettel's best time was set on the hard tyres, while Alonso set his best on the test tyres.
The session passed without serious incident, save for a couple of wide moments and a spin for Felipe Massa at Pinheirinho.