Williams' Paddy Lowe acknowledged his team's defeat at the hands of Force India in 2018 as its rival's development simply outpaced that of the Grove-based outfit.
In 2016, Force India snatched fourth place in the Constructors' standing in the closing stages of the season but this year Williams was left behind by the pink squad from the outset.
Lowe points to the teams' respective development pace as the main performance differentiator, and admits Force India had the upper hand.
"We started the season with a car that was generally quicker than theirs. We've ended generally slower," says Lowe.
"So we have lost ground to Force India on performance. We have both been developing through the season at a rate you don't see - and they've done a better job.
"It's our job to recover that and more over the winter. We need to make a bigger step with the new car than they make.
"Renault have also come through with better performance through the season."
Lowe also invoked Lance Stroll's insignificant contribution to the team's performance in the early part of the year as the rookie learned the ropes of Formula 1.
"The first half of the season, when we had quite often the quicker car, we weren't scoring the points particularly on Lance's side, when the opportunities were presented," said Lowe.
"With Lance new to the sport this year, it was always going to be a more difficult first half than second half. Those two factors were enough for Force India to get a stronger tally."