Jari-Matti Latvala says Ford must capitalise on a near-perfect start to the Rally of Portugal.
The factory Fiesta RS WRCs ended the opening day first and second, while championship leader Sebastien Loeb rolled out of the rally on SS3 on Thursday night.
Despite heavy rain in the third gravel stage of day one, Latvala and his team-mate Petter Solberg emerged at the top of the leaderboard, vindicating the British team's selection of running order position.
Ford had opted to run at the back of the pack for last night's competition, while the works Citroens opted to run at the front.
The first two gravel stages favoured the Fords, running in relatively dry conditions which forced Mikko Hirvonen and Sebastien Loeb to sweep the loose gravel clean. The third would probably have cleaned as well, but the Fords were hampered by torrential rain which arrived while they were in the stage.
Latvala said: "I am really happy our tactic paid off. We spent a lot of time thinking about it and it has really paid off now. I have to admit, I was a little bit worried when I saw the rain coming in the service park, but it went well for us.
"Ford has the good cards now, but we need to use them very wisely. There are still 400 kilometres to go in this rally, we have to stay clever and stay calm."
With Loeb out of the rally, Latvala said the approach from the Frenchman's team-mate Hirvonen would be key to how the event played out for the next three days.
"It will be interesting to see what he does," added Latvala. "I don't know if Citroen will let him fight. I think he will fight at the start of the second day and see what happens."