Williams' senior race engineer has said that the team are still working hard to close the gap to the midfield and salvage something from their torrid season so far.
George Russell and Robert Kubica have been backmarkers all season, scoring just one point thanks to Kubica's tenth placed finish in a manic German Grand Prix.
Senior engineer Dave Robson told Autosport that the steps the team made in Hungary were "testament to an awful lot of work both at the factory and here".
"I wouldn't say everything was completely vindicated yet.
"We'll have to see what happens at Spa and beyond, but I think the progress is there."
Chief engineer Adam Carter added: "In this industry things are constantly evolving, and you're in competition, and you have to make a conscious decision to stop, rebuild and then start going again for the greater potential and opportunity afterwards.
"That, for me, is one of the hardest things."