George Russell says it felt "strange" when he was unable to keep racing for Mercedes in Lewis Hamilton’s place after his near-win in Bahrain.
The 22-year-old Mercedes junior was called up at short notice when Hamilton tested positive for covid-19 - but had to return to his back-of-the-grid Williams cockpit a week later.
"To be honest, it felt strange to go back," he is quoted by Speed Week.
"Before the Bahrain weekend, I really wanted to be able to contest the two races for Mercedes. I would then have taken the first weekend as a lesson and had no more excuses in Abu Dhabi.
"But the guys at Williams gave me this chance in Formula 1, working so hard for me over the past two years. It is my duty to do my best for them," Russell added.
For 2021, Williams has appointed a new team CEO - former Volkswagen and McLaren chief Jost Capito.
He told the Alte Schule podcast: "With the new team ownership, Williams has an opportunity to restructure.
"This is so important, because last season the team earned zero points and there is no lower than that.
"We shouldn’t expect miracles this year, because we won’t be able to make significant changes to the car. And with the covid-19 crisis, without a moratorium on development, the gap to the bigger teams will only increase," said Capito.