Marussia team boss John Booth believes the United States Grand Prix qualifying results show his squad is now faster than rival Caterham.
For the first time this season, both Charles Pic and Timo Glock qualified ahead of Caterham drivers Heikki Kovalainen and Vitaly Petrov.
Kovalainen said after qualifying that he was convinced Caterham was the better team and that it will beat Marussia on Sunday.
Booth, however, feels the result is the reward for his team's development push since the halfway point of the season.
"Today is an important day for the whole team as it represents the culmination of the aggressive development programme we have undertaken since the mid-season," said Booth.
"We have demonstrated that we are now faster than the Caterhams after both cars achieved the objective of outqualifying them."
Glock was the quickest of the Marussia drivers in 19th position, finishing nearly a second ahead of the fastest Caterham.
The German was delighted with his day.
"We are almost 0.8 seconds ahead of the Caterhams and we have to be very pleased with that," he said.
"This is great development from the team and although it seems like we remind everyone every race just now, we've managed all that without the advantage of KERS and that is a significant point.
"I'm very excited for the race and I hope we can continue the good work."