
Lewis Hamilton topped the timesheet in the first practice session at the Singapore street circuit.
Hamilton was ahead of championship rival Felipe Massa of Ferrari, clocking a time of one minute 45.518 seconds.
The 23-year-old Englishman had looked set to do the same in the second session after leading for most of the way.
But Renault driver and former team-mate Fernando Alonso produced a superb last-ditch lap time of 1:45.654secs to edge Hamilton by just 0.098secs.
Hamilton admitted he found the Marina Bay circuit more challenging than Monaco, saying: "It is a very physical circuit, more than I expected actually.
"I would say it requires double the energy of Monaco over a single lap. One lap around here is like two laps around Monaco."
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