Williams's chief operations engineer Mark Gillan says the team's return to podium contention in Valencia was more due to maximising its potential than any development breakthrough.
After ending its victory drought with Pastor Maldonado's Spanish Grand Prix triumph, Williams had tough races in Monaco and Canada, scoring just one point from Bruno Senna's Monte Carlo 10th place. But in Valencia, Maldonado qualified third and was battling for the same position at the end of the race when he collided with McLaren's Lewis Hamilton.
"We were frustrated the last couple of events. We had seen through the running that we had been quick, but we never actually got to demonstrate it," said Gillan.
Although Williams brought new parts to Valencia, Gillan said getting the setup right had been the biggest breakthrough.
"The upgrades are important but it's the balance that has been crucial," said Gillan. "You get a base lap time, which goes up with how good your base car is, but it's all about getting the balance. Not just the mechanical, the whole balance of the car in the operating window for the tires.
"In upgrades there may be a tenth or two tenths, but between the tire working and not working there's multiple tenths. So it is very important. And it's so tight. You saw in Q2 how ridiculously small the gaps are. Two tenths puts you up 10 places."
Gillan said that while Williams was pleased to have turned its form around after several challenging seasons, it was frustrating not to deliver more consistently.
"What's really pleasing from our side is the changes that we made from last year to this year, the evolution or performance of the whole team operation," he said. "It's very pleasing to be performing well, but we need to do it on a regular basis. We had a very good result in Barcelona, then we had two disappointing results. What was more disappointing was that we knew we could have been better.
"It's a whole team thing. It's strategy, setup, management, the understanding and the analysis is all very important. It's a really interesting year because everybody in the team, including the driver, can make a big impact."