McLaren's Lewis Hamilton claimed his second win of the Formula 1 season in style as Red Bull's Sebastian Vettel handed his Brawn title rivals a boost.
A penalty dropped Vettel from second to fourth, just ahead of Brawn's Jenson Button and Rubens Barrichello.
The error leaves Vettel 25 points behind Button in the standings with 30 points remaining on offer. Barrichello is 15 adrift of his team-mate.
Toyota's Timo Glock took second place ahead of Renault's Fernando Alonso.
However, the finer details of the podium paled in the face of developments in the drivers' championship.
Vettel set off in hot pursuit of Hamilton after an early challenge from Williams' Nico Rosberg faded, but squandered his hard work when he broke the pit lane speed limit during his second stop for fuel and tyres.
As if the resulting drive-through penalty were not enough, Vettel also damaged his diffuser on a kerb. Red Bull team-mate Mark Webber can no longer win the drivers' title after he suffered brake failure on lap 46.
And while Red Bull could still conceivably win the constructors' championship, Brawn are now 42.5 points clear with a maximum of 54 points on offer.
Their rivals' misfortune will have been music to the ears of both Button and Barrichello who, for much of the race, had laboured unremarkably from grid positions of 11th and ninth respectively.
The pair struggled to make an impression up to the appearance of the safety car following a crash involving Force India's Adrian Sutil and BMW's Nick Heidfeld on lap 21.
And while the safety car helped Hamilton, who had just pitted, fellow Englishman Button watched his fuel advantage over a number of rivals, carried over from Saturday's qualifying, evaporate.
But the Brawns kept plugging away and as Red Bull's challenge crumbled, Button pushed up to fifth, just ahead of Barrichello.
Button pleased with fifth place
Nursing brake problems for the final few laps, Button crossed the finish line knowing he has edged a little bit closer to the title, which he can win in Japan next weekend if he gains five points or more on Barrichello.
"I got stuck behind Heikki Kovalainen for quite a few laps of the race but when he pitted I was able to get past him - I'm very happy," said the Englishman.
"I could see Rubens pulling away very slightly and couldn't do anything, but I was happy to get Kazuki Nakajima off the line, that was key for me and made my race really."
Vettel expressed mystification at his drive-through penalty, telling BBC Sport he was "very surprised" to be called back through the pit lane.
"I wasn't in a rush and can't really explain why I got caught - it was maybe an electronics issue," he suggested.
"With that penalty and the damage to my car by the end - it was falling apart! - fourth place was the best we could do." There are now three races remaining this season, in Japan, Brazil and Abu Dhabi, which makes its F1 debut as the season finale.
Thunder storms threatened the Marina Bay circuit as the season's 14th grand prix began, but the weather remained dry, sparing drivers an introduction to night racing in the wet.
Rosberg, starting third on the grid, was the biggest winner as the cars got away without incident, sneaking ahead of Vettel on the first corner.
The Williams driver held second place for the opening 25 laps, but surrendered his advantage having been issued a drive-through penalty for crossing the white line on his way out of the pits following his first stop.
Rosberg, who later admitted he had been "very stupid" to cross the line, re-emerged from his penalty in 14th place and finished 11th, ruining what Williams had hoped would be a strong weekend performance.
Hamilton, by contrast, barely blinked with Rosberg in his mirrors, and shrugged off the challenge of a reinvigorated Vettel once the safety car departed at the end of lap 25. An early problem with Kers was the defending world champion's only major concern and, once Vettel had dropped back following his penalty, Hamilton's race victory was all but assured.
"It was a very, very tough race, I think I can speak for all of us," he said. "Conditions made it very tough but it was pretty straightforward for me.
"I knew I was longer than the guys around me so all I had to do was keep Vettel behind me. I felt I drove quite a nicely-controlled race."
Hamilton's team-mate Kovalainen, who spent a large portion of his race trying to contain Button, came home seventh, with BMW's Robert Kubica eighth.
Glock was the happy beneficiary of early jockeying for position between Webber and Alonso.
Webber, deemed to have overtaken Alonso illegally having strayed off the track, had to move aside to let Alonso and Glock, whose Toyota was ahead of the Renault, through.
That left Glock ideally-placed to take advantage when Vettel and Rosberg ran into trouble later in the race. Alonso, who won the now-infamous 2008 race in Singapore, had - by the standards of those around him - a quiet but nevertheless impressive race to cruise into third place.
"The race was fantastic and the result is great for us, to get our first podium of the season," said the Spaniard.
Alonso was also quick to pay tribute to Flavio Briatore, the former Renault team principal who left in the wake of the race-fixing scandal.
"It was not an easy weekend for anybody, especially after last week," said Alonso.
"But 700 people work on this car and they - and Flavio, of course, because we're all here because of him - deserve this success."
The Spaniard's team-mate, Romain Grosjean, retired with high brake temperatures just three laps into the race.
Grosjean was joined by Sutil and Heidfeld after their collision, following a spin from Sutil.
Heidfeld's retirement completed a grim day for the German, who had been kicked to the back of the grid for running underweight in qualifying.