Williams's chief operations engineer Mark Gillan believes his team will have strong race pace in the Canadian Grand Prix, but is concerned about its qualifying form.
Pastor Maldonado was 13th in both Friday sessions in Montreal, while his teammate Bruno Senna had DRS problems in the morning and crashed in the afternoon.
"We are happy with our long run pace but still have work to do to optimize the car for qualifying," said Gillan.
Maldonado felt that Williams was still in generally good shape.
"We completed all of the things that we had planned for the session so we have had a productive day and are in a good place heading into the weekend," he said. "We still need to work on the setup to get the right balance, but overall the car felt good and was consistent, particularly on the long runs. We have also brought some upgrades to this race and they were performing well which is encouraging."
Senna remained optimistic that he can make up for his Friday problems in final practice.
"I had DRS issues during the morning session and have limited experience of this circuit so today was about getting my eye in and seeing how far I can push the car," said Senna. "Obviously I pushed too hard towards the end of P2 and hit the wall, which is disappointing. Nevertheless, we have made some improvements on the overall package and tomorrow morning I can go out and try to fine tune the setup to get a good result on Sunday."