Williams' head of vehicle dynamics Dave Robson says it was a "nice surprise" for the team to start 2023 as Formula 1's second most improved team behind Aston Martin.
Williams languished at the bottom of the 2022 championship and arrived at last month's Bahrain pre-season test with caution, playing down any hopes it would be able to move up the grid after a winter spent in limbo.
But in Bahrain the team's lead driver Alex Albon grabbed a point after reaching Q2. While neither he or rookie team-mate Logan Sargeant managed to escape Q1 in Saudi Arabia, Albon only missed the cut-off by a tenth.
Williams could still finish at the bottom in 2023, but its early pace looked promising, especially for a team that has operated without a technical director or head of aerodynamics since December following the departure of FX Demaison and David Wheater.
"Yeah, we came out of the test thinking we were better than we were last year, but maybe still as pretty much one of the slower cars," Robson said when asked by Motorsport.com if his team's early pace has been surprising.
"Bahrain was generally a bit of a surprise. [Jeddah], thinking that the circuit here would suit us a bit more, it's probably slightly less of a surprise.
"But it's still early days. People seem quite up and down as far as I can see, session by session and even in qualifying, it looked like team-mates in the same car were quite up and down, so it's probably still a bit early by the moment.
"It's all going well, it was a nice surprise in Bahrain and long may it continue."
Robson explained Williams has been able to find significant gains compared to last year's FW44, with one particular goal to make the car less of a one-trick pony.
The Grove team's 2022 car lacked downforce, but its inherent low-drag characteristic allowed it to flourish at high-speed, low-downforce circuits, with Albon stand-in Nyck de Vries' ninth place at Monza a particular highlight.
"We've made good progress because we knew when the last year's car came out, it had some particular weaknesses," Robson said.
"Throughout last year and into this year we've worked on those, and I think they probably yielded a reasonable step up in performance.
"We did see quite a lot of it on FW44. It was obviously quite poor at the start of the year and it did get better.
"I think we managed to take another step at the start of this year. That said, of course, we've only been to two circuits, so I'm sure there'll be others where that improvement is less evident."
Additional reporting by Jonathan Noble