Sergio Perez reckons he extracted the most from his car in qualifying at Sakhir but feared that an "old engine" installed in his Racing Point could weigh on his performance in Sunday's race.
Perez qualified fifth in Saturday evening's shootout, missing out on a spot on the second row by just 0.177s.
While satisfied with his performance, the Mexican felt that the mileage on his Mercedes power unit, a legacy of the end of the season, had curbed his straight-line speed on Sakhir's rapid outer loop.
"I was pleased with the result," he said. "We were working all weekend on the car and finally we were able to find some rhythm.
"Given that I have such an old engine, I think we were losing a bit as the qualie progressed with the straight-line speed, which is not ideal."
But Perez believes the slight loss of power could also impact his ability to overtake in Sunday's race, leaving him with a struggle on his hands, unless he can improve his fortunes with the help of a handy tyre strategy.
"It will be important to make it to the end," he said. "I don't think we're in a great position to race because we can hardly overtake people.
"The strategy will be very important because even in qualifying we could see that tyre degradation was a factor.
"The key could be making the soft tyre last longer in the first stint and, hopefully, that will open up some opportunities through strategy.
"I think we’re capable of making that work and the race could come to us, but we need to focus on putting everything together until the final lap and making sure we score good points."