Lando Norris scored his maiden F1 victory on Sunday for McLaren, the team's first since the 2021 Italian Grand Prix.
The turnaround from the team's position last year has been heralded, with developments allowing McLaren to leap ahead of Aston Martin and Mercedes in the pecking order and, on occasion, challenge Red Bull and Ferrari at the front.
Pointing to this as a source of inspiration for Mercedes, Russell conceded that his team needs to "make changes quick" in order to recover from a disappointing start to the season.
"McLaren qualified P17 and P18 12 months ago in Miami, and [on Sunday] they won. So it shows what's possible when they get things right," Russell said after the race.
"But right now we don't have things right."
Mercedes, whose last win came at the 2022 Brazilian GP thanks to Russell, endured another difficult weekend in Miami, failing to score in Saturday's sprint after Lewis Hamilton was penalised for a pitlane infringement.
On Sunday, Hamilton finished down in sixth, while Russell had to settle for eighth place.
Asked if the problems in Miami were down to tyres or something else, Russell said: "I don't really know, to be honest. You know, on a good day we're P5. On a bad day, we're P8 and today [Sunday] was a bad day, and we finished P8.
"I think we have to accept that we are the fourth-fastest team at the moment. The lap times don't lie. And the championship [standing] doesn't lie. This is where we are.
"And as I said, we're fighting for the P5 to P8 region week in and week out now."
The result left Mercedes 80 points behind McLaren in the constructors' championship, but team boss Toto Wolff also saw positives in his rival's victory.
"They have made such a massive step since last summer and they won fair and square and this is with a Mercedes engine and that is so important for all of us to see that you can make these steps if you're bringing the right upgrades and do the right work, so I see only positives," said Wolff.
While its W15 car showed some signs of progress earlier in the season, Wolff conceded it has been a "painful learning curve" for the team.
"The car is very strong in high speed, the ride is better although not on the level of the other ones," he said.
"The car just doesn't turn in low speed and you don't want to have a car that is either good in low speed or in high speed, you need the two of them and that's why they point us in some of the right directions.
"It's been a painful learning curve and it's still not satisfactory, but the situation is more encouraging now."
Mercedes introduced several upgrades in Miami, including a new floor and edge wing arrangement, in what Wolff labelled an "all in" effort from its design office.
Additional reporting by Mandy Curi.
