Valtteri Bottas hailed an increase in confidence in his FW36 for his fourth place on the Spanish Grand Prix grid.
The Williams driver came to the fore in Saturday's qualifying at the Circuit de Barcelona-Catalunya.
Clocking a 1:26.632 on his final flying lap, Bottas clinched fourth place on the starting grid, his best position this season.
It was a great recovery after finishing outside the top ten at the end of Friday's running, some three seconds off the pace.
"It has been quite a tough weekend up until now," he said.
"I had to build a lot of confidence but it all came together when it mattered and I managed to get a good lap.
"We have made some set-up changes since FP3 and they worked well but it will be even better in the race.
"It's difficult to overtake here and so qualifying is important."
The Williams driver is predicting a closely-fought battle behind the Mercedes as those behind fight it out for the final podium position.
He added: "It's going to be a close race behind the Mercedes and so I am really looking forward to tomorrow."