Sergio Perez held off the challenge from Red Bull's Daniel Ricciardo and finished the 57-lap race on Sunday in third place, just 0.422 seconds ahead of the Australian who was on the softer tyres.
Perez's teammate Nico Hulkenberg finished fifth giving Force India 25 points from the race, their best showing in F1.
"There is every reason to expect further podiums from Force India. All teams are still working on optimising their power units and aero performance and we too will be working on improving the car," Fernley told PTI from Bahrain, a day after his team stepped on the podium only for the second time.
Though Force India and other teams on Mercedes engines have done well in the early part of the season, one can expect the Renault powered Red Bull and team Ferrari to bounce back in the upcoming races.
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A lot of development work is expected to take place in the two-day mid-season testing beginning at the Sakhir Circuit on Tuesday.
Fernley said their focus would be on "enhancing" the performance of the car.
With their best ever finish in Bahrain, Force India are second in the team standings with Hulkenberg (28 points) and Perez (16) being third and ninth in the drivers' championship.
The Red Bulls of Ricciardo and Sebastian Vettel seriously threatened the position of Force Indians who were doing their stint on the harder compounds.
"Assuming no mechanical issues, we would have been third and fourth without the safety car. Sergio and Nico drove superbly for track position between themselves and then protected each other when needed to see of the Red Bull challenge," added Fernley.
The next race is in Shanghai on April 20.