Marussia team principal John Booth is certain that his outfit has a car capable of taking the fight to Caterham after a strong showing in Friday practice in Singapore.
Timo Glock has outpaced lead Caterham driver Heikki Kovalainen so far this weekend, lapping over three tenths of a second faster in Friday's second session.
Although Marussia has not introduced any upgrades this weekend, except for additional brake cooling and a 'monkey wing' to suit the high-downforce circuit, Booth believes that the major package introduced by the team at Spa is now showing its full potential.
"We can race Caterham," Booth told AUTOSPORT. "Although to be fair to Heikki Kovalainen, he had a lap spoiled on his first run on option tyres, so he'll have another couple or three tenths.
"We felt that we made a step forward at Spa and Monza, but those tracks were the least advantageous configuration for us as they are low downforce.
"But we were still very encouraged by both of those showings. We hoped that it would leapfrog us up once we got to a higher downforce circuit.
"Since introducing the package, we have been optimising that aero set-up and everything pointed towards it being a step forward."
Booth added that the strength of his driver line-up also gives him confidence for Singapore.
The Frenchman ended up just over six tenths behind Glock in Friday's second session.
Asked if having a Singapore specialist like Glock in the car was a boost, Booth replied: "It is. But Charles did an amazing job to get so close to Timo having never seen the circuit before.
"I think we'll have two challengers again. It does make life easier if we have two challengers. If something happens to one, the other is there."