The longest car on the Formula 1 grid was bound to be handicapped around the circuit's tight and twisty streets, even though the team's calculations suggest the extra downforce from its concept outweighs a 0.1 seconds loss from its wheelbase.
The team worked hard to improve its platform, and there were a host of subtle changes introduced over the weekend that helped lift it into contention - even though Red Bull was ultimately too quick.
Mercedes' designers arranged six vortex generators atop the W09's sidepod in Monaco. Having already tested the appendages in the post race test at Barcelona, the team was confident the generators could add performance.
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Angled out reasonably aggressively, the small flow-adjusting devices were installed in order to improve the aerodynamic envelope of the sidepods, delaying flow separation and working the airflow over the sidepod harder.
The team made significant changes to its sidepods for 2018, altering internal components such as the exhausts and radiators as it tightened the external bodywork and chased even more performance.
Chasing internal flow performance sometimes comes at the cost of the overall aerodynamic achievement, meaning changes of this magnitude have often had the reverse effect for teams.
That means the vortex generators might not be seen again until the prevailing circuits characteristics support their use.
Cooling is also a factor at Monaco, as the low speeds of the circuit made it harder to get the normal amount of air flowing through the car.
That is why Mercedes fitted a new engine cover, with a different shape that featured a top-fin opening like it had in 2017.
The team also made a major front suspension change on Saturday morning after suffering vibration issues with the version it had been running until that point.
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