After the Japanese Grand Prix, Force India was only 17 points clear after losing 37 points to the Swiss team in just four races.
But in the past two races, Force India has scored 15 points while Sauber has failed to pick up any, giving the Silverstone-based squad a lead of 32 points with two races remaining.
Fernley has also not given up hope of closing the 18-point gap to McLaren.
"We started to be able to get back on top of things and show a bit more pace in Japan and we've managed to carry it from there," Fernley told AUTOSPORT.
"India and Abu Dhabi were very good for us and most importantly, they have not been so good for Sauber, so hopefully we have broken the tow a little bit on that battle.
"Now we turn our attention to McLaren."
Paul di Resta, who finished sixth in the Abu Dhabi Grand Prix believes Force India can continue to score points in the final two races of the year.
"If we execute what we did in Abu Dhabi and in the previous grand prix, which is a perfect race, we can get the points," said di Resta.
"If we are just a little bit off that and other people have a perfect race, we seem to be just off the top 10.
"Credit to everyone in how the momentum has carried from Suzuka so we have the car in a window where it gives you confidence, you can drive it hard and where you can extend stints.
"Right down to the strategy, the engineers, the mechanics, everyone did their job spot on.
"That's what we can do and that was the job we were doing earlier in the year."
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