Force India team principal Vijay Mallya admits his team have their work cut out for them in the battle to stay ahead of Williams.
The Silverstone-based squad are currently fourth in the team standings, but their advantage over Williams have been reduced to just two points after the latter scored 27 points, including a third-place finish from Valtteri Bottas, in Austria.
Force India by contrast left Spielberg with just 10 points and Mallya knows it will be a difficult battle with their Grove counterparts until the end of the season.
"From the pre-season test Williams has shown that it is very competitive this year, and they have the Mercedes power package this year as well," he told Crash.net. "They have been quick in qualifying but were not as brilliant in race pace. But in Austria they showed both and it was only a matter of time before it all came together for them.
"So they are going to be a serious competitor. [On Saturday] I was quite worried with Williams starting with both cars on the front row that they might have scored more points than us and passed us in the Constructors' Championship. Fortunately we also scored points and minimised that so we still retain fourth, but they are close and it's going to be a close fight going forward."
Next up is the British Grand Prix, a home race where Force India know they can't afford to take it easy.
"We have got to take every race seriously and do our very best. Done are the days where we can say certain circuits suit us and certain circuits don't suit us; if we want to do well in the Constructors' Championship we need to perform well on all circuits," Mallya said.
"Of course, emotionally Silverstone is very important for us. So if we come away with a strong result the whole team is happy including those back at the factory who don't necessarily get to go to all the races. So Silverstone is important from that point of view."