With Mercedes' title hopes having evaporated thanks to Sebastian Vettel's five consecutive victories, the German car manufacturer has its own theory as to why its challenge has faded.
Renault-powered teams have locked out the podium for the past two races, and Mercedes motorsport boss Toto Wolff thinks Red Bull and Lotus could be benefitting from advanced mapping settings and exhaust flow control.
When asked by AUTOSPORT about the current form, Wolff said: "I think what you can see is that Red Bull from Singapore onwards looked like having made a big step forward, and then in Korea the Lotus made a big step forward of 0.2-0.4 seconds.
"The question we need to look at is what they do in terms of engine mapping maybe.
"Is there something there? The blowing strategy maybe?
"In terms of development over the last races, we seem to be behind. Is it because there is something we don't understand in terms of mechanical set up?
"Or did first Red Bull and then Lotus do something which is related to engine strategy?"
Wolff says getting to the bottom of why Red Bull and Lotus' form has improved is vital for his outfit if it is going to finish second in the constructors' championship.
But he admits the team will have a tough decision to take if they feel they need to respond because it could mean pulling some resources back from the 2014 project.
"There are three points to look at," he said. "First, did we miss something and if so, why?
"Second, we need to balance the resources right in terms of 2014 versus 2013.
"Then third we have to be looking at finishing second in the championship.
"That is our target and we can't let that go."
Renault has been at the forefront of sophisticated engine mapping over recent years to improve driveability.
The legal use of engine cylinder cutting and exhaust blowing to the floor area to help in its quest has often wrongly been interpreted as evidence of traction control.
- Toto Wolff
- Red Bull
- Sebastian Vettel