Marussia boss John Booth admitted his team was really feeling the pressure during the final stages of the Abu Dhabi Grand Prix seeing rival Caterham's position.
The squad moved ahead of Caterham - and into 10th place in the constructors' championship - with a 12th-place finish by Timo Glock in the Singapore GP.
A similar result by Caterham would move the team ahead of Marussia as it has more 13th-place finishes than its rival with two races to go.
Caterham's Heikki Kovalainen was running in 13th place in the final part of the race, meaning another retirement would have been costly for Marussia.
Booth said Sunday's race was a reminder that 10th position is far from guaranteed yet.
"A nailbiting race pretty much from start to finish, although it was in the final 10 laps that we really felt the pressure," admitted Booth.
"We could do little about the retirements ahead of us, so we had to simply concentrate on our own very hard-fought race with Caterham.
"Today has reminded us that P10 is far from 'a given' - we have to keep fighting to keep it."
Glock finished the Yas Marina race in 14th place while team-mate Charles Pic retired on lap 42.