Briton quickest on supersoft tyre ahead of team-mate Nico Rosberg and Ferrari's Fernando Alonso.
The pair had been evenly matched in the early part of the session on the Soft compound Pirelli tyre but when the pair moved to the quicker Supersoft compound rubber, Hamilton found a new impetus and his first flying lap ended with the Briton 0.7s ahead of Rosberg, who only shaved a tenth of a second off his best time on his first lap on Supersofts. Rosberg eventually found more time on the Spielberg track but in the end he could only cut the deficit to 0.377.
As with the morning session, Fernando Alonso was third-fastest, though the Spaniard ended the session almost a second down on Hamilton. Fourth place went to Mercedes-powered Williams driver Valtteri Bottas, with team-mate Felipe Massa fifth.
After a difficult morning session in which both its drivers struggled, the afternoon was much more productive for Red Bull Racing. Sebastian Vettel finished sixth fastest, though 1.265s down on Hamilton, while Daniel Ricciardo finish eighth, just behind McLaren’s Jenson Button. Vettel emerged late from the Red Bull garage after his car required a new floor following a big spin in the morning. Ricciardo, too, had the floor of his RB10 changed following his own morning spin.
As in the morning, Kevin Magnussen ended the session in ninth place ahead of Jean-Eric Vergne, the Frenchman once again taking Toro Rosso into the top 10.