The German, who was again booed on the podium, leads Ferrari's Fernando Alonso, who finished second, by 60 points with just 150 still available in the remaining six races.
It was Vettel's third straight win in Singapore and followed victories this season in Italy, Belgium, Germany, Canada, Bahrain and Malaysia.
"The start was quite hairy, Nico had a good start - better than me," Vettel said. "I didn't get going initially, but fortunately he went in a little bit deep and I could get him back, which was crucial as we had very good pace."
Lotus's Kimi Raikkonen was third with Mercedes drivers Nico Rosberg and Lewis Hamilton in fourth and fifth.
Image: © Getty
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