All pump operators here have adjusted their prices downwards since Esso and Shell reduced rates by around three cents last Friday.
Caltex and Sinopec responded to that reduction last Saturday.
Their 92-and 95-octane petrols are now $1.95 and $1.99 per litre before discount respectively, according to Fuel Kaki, a pump price tracker managed by the Consumers Association of Singapore.
Sinopec's 98-octane petrol is now $2.36 a litre, matching Esso's equivalent price, and two cents lower than Shell's.
Caltex has priced its so-called "ultra premium" 98-octane petrol at $2.48 a litre, lowering its price by four cents.
Sinopec's equivalent to Shell's V-Power is now $2.51 a litre, down from $2.55 previously.
Caltex and Sinopec are pricing diesel at $1.67 a litre, matching the price at Esso and Shell.
SPC still offers among the lowest prices, having resisted a round of increases by the others two weeks ago. While its 92-and 95-octane petrols are the same prices as the others, its diesel is three cents lower at $1.64, while its 98-octane petrol is $2.33 - three cents lower than the next lowest price.
The latest prices come on the back of relatively unchanged wholesale prices. For instance, RBOB Gasoline, a publicly traded commodity and a proxy for wholesale petrol price, had dipped slightly last week, but is still noticeably higher than two weeks ago.
Industry watchers reckon SPC's resistance to the previous round of price increases had contributed to the latest downward adjustments.
Oil industry consultant Ong Eng Tong said: "SPC not increasing prices must have affected their business."
It would not be the first time SPC's lone resistance persuaded other pump operators to backtrack on their price increases.
Early this year, the Chinese-owned company also resisted a round of price increases, which saw all the other players raising petrol and diesel prices by three cents a litre from Jan 6. Within a week, the other players had reverted to their previous rates.