Sainz will lose his seat in 2025 to Lewis Hamilton, even though he is the only non-Red Bull driver to win a race since 2022.
When asked whether the Spaniard was underrated at the Australian Grand Prix, Norris came to his defence.
“There's no reason anyone should think he's underrated," he told the media.
"I think for the people who know him, know what he's capable of doing, know his effort level, his approach and dedication to wanting to be one of the best, exactly like he's proved today, and over the last couple of weeks.
“I'm sure you have plenty of drivers who probably wouldn't have tried as hard and dedicated so much of their time and effort to trying to recover and get back in the race car. And I think that's just one example of it," Norris continued.
“But for the people who know what he's capable of doing, you would never ever say he's underrated. And yeah, of course, results are always a bit of a point to show and people on the outside just easily judge things from what you see on TV.
“But when you've worked with him, when you know what he's capable of doing, and when things click, they click very well and he has performances like he does this weekend.
“And I would say all year, he's proved to be a step up from maybe what he has been last year. Yeah, you're silly if you underrate him.”