SPA- Lewis Hamilton topped the times ahead of his Mercedes team-mate Nico Rosberg in Friday's twice red-flagged second free practice session ahead of this weekend's Belgian Grand Prix. The 29-year-old Briton, who was second behind Rosberg in the morning session, clocked a best lap of one minute and 49.189 to finish clear at the top of the times on a typically incident-filled day at the old Spa-Francorchamps circuit in the Belgian Ardennes.Rosberg was six-tenths of a second slower than Hamilton to finish second ahead of two-time champion Fernando Alonso of Ferrari, Felipe Massa and Jenson Button of McLaren on a rare dry day at the track. Valtteri Bottas was sixth for Williams ahead of Russian rookie Daniil Kvyat of Toro Rosso, Australian Daniel Ricciardo for Red Bull, Danish rookie Jan Magnussen in the second McLaren and Nico Hulkenberg for Ford India.The session began under a heavy black cloud and produced two major 'red flag' accidents, but nobody without anyone being injured. The first came when Venezuelan Pastor Maldonado lost control of his Lotus car in the approach to Pouhon and hit the barriers heavily. He was quickly in communication with the team via radio to say he was unhurt, but his car was seriously damaged and he was out for the rest of the session. The second red flag came when Mexican Esteban Gutierrez spun off at Blanchimont in his Sauber. "Can you get back to the garage?" the team asked him. "It is the gear box...Something break completely," he replied. In the intervening periods of on-track action, Alonso clocked 1:51.693 to go top before Hamilton, who was second behind Rosberg in the morning practice session, regained the ascendancy by taking half a second out of the Spaniard's best time.Ricciardo, Red Bull's sole representative in second practice as four-time champion Sebastian Vettel waited for an engine change, also ran off the circuit without causing any damage. With 40 minutes to go, all the leading drivers switched to softer tyres and Hamilton stayed on top while Frenchman Romain Grosjean reported that his Lotus was "all over the place" and difficult to drive. Rosberg then swept to the top of the time-screens with a lap in 1:49.793, but was swiftly replaced as Hamilton responded in 1:49.189, the way it stayed until the flag. Earlier, Mercedes executive director Toto Wolff gave an insight into how the team had rebuilt rapport after their discord in Budapest. He said the situation, after Hamilton had ignored team requests to allow Rosberg to pass him, had "needed a little bit of mediating, management, caressing, hard words..."And, he added: "You cannot expect it to run super-smoothly. You don't expect when your team-mate has one more stop to do that you make his life difficult. On the other hand you cannot ruin one's race by expecting him to lose a couple of hundred metres. "It was a matter of the words used not the principle. We probably shouldn't have said to Nico that Lewis was going to let him through, we should have said he won't make your life difficult."