The Spaniard recorded the best lap of the weekend around the floodlit Marina Bay circuit, clocking one minute 45.390 seconds in the third qualifying session to edge out Red Bull's Sebastian Vettel [ Images ] and the McLarens of Lewis Hamilton [ Images ] and Jenson Button [ Images ].
World championship leader Mark Webber [ Images ] will start Sunday's race behind all four of his title rivals after qualifying in fifth position on a circuit where he has yet to finish a race.
Alonso has scored more points than any other driver in the last four races, including a win in Monza two weeks ago, and the Spaniard appears to have hit form at the right time and will be confident of eating into his 21-point deficit in the standings.
Three points further back and with five races remaining, Vettel desperately needs a win to haul himself back into the mix. The German dominated practice on Friday and Saturday but was unable to turn his supremacy into a pole position.
Singapore's narrow street layout makes overtaking virtually impossible and although Alonso tasted victory in the inaugural race in 2008, he will be concerned that his Ferrari [ Images ] team mate Felipe Massa [ Images ] suffered a mechanical failure in qualifying.
The Brazilian stopped on the track in the first qualifying session with what his team described as an "electronic management of the gearbox problem" and was unable to record a timed lap.