In FP1, Alex Albon was an impressive third fastest, and the Thai/British driver then underlined the speed of the car by repeating the performance in FP2.
However, while Albon has been an occasional visitor to the top 10 this season, what caught the attention of rivals was that rookie Logan Sargeant was fifth fastest in FP2 in what was by far the best showing of the American's season so far.
Williams introduced a new aero package in Montreal, where Albon finished seventh on a track where the updates – aimed at high-speed corner performance – were not expected to provide much benefit.
The revised car's potential was perhaps not obvious over the Austrian sprint weekend, although Albon qualified 10th and had a solid race to 11th.
"We need to go and have a look at the data and try and understand it," Robson told Autosport regarding the Silverstone form.
"We did think we'd be a little bit better here back at a high-speed circuit with the package we fitted in Canada. I don't think we really saw the best of it until perhaps here.
Source: Autosport