Russell unleashed some encouraging signs of increasing competitiveness from Mercedes’ W13 challenger as he was just pipped to the benchmark time in first practice, before leading Ferrari’s Charles Leclerc by a tenth of a second in FP2.

It marked unfamiliar territory for the once-dominant world champions amid what has been a woeful start to F1’s new rules era, with Mercedes lagging nearly a full second behind Ferrari and Red Bull in the opening four races. 

But Mercedes sent a statement with much-improved pace on the first day of running for F1’s inaugural race at the Florida city, and the team’s impressive showing was not lost on rival Red Bull team boss Christian Horner. 

“I have said since pre-season it is only a matter of time before [Mercedes] sort themselves out,” Horner told Sky. “That is starting to happen.

“They are getting on top of their issues and looking competitive.”

What is behind Mercedes’ improved showing? 

The eye-catching performance has coincided with Mercedes introducing their first significant upgrades of the season in the United States. 

Mercedes debuted a lower-drag rear wing and a revised front wing on both Russell and Lewis Hamilton’s cars in Miami as part of a push to get on top of the porpoising that have severely afflicted the team’s performance. 

After first practice, Mercedes’ head of trackside engineering Andrew Shovlin acknowledged it had been “an encouraging start to the weekend”.

Explaining the updates to Sky, Shovlin said the new front wing endplate gives “more downforce for the same drag and the rear wing’s a more efficient wing than the one we’ve been running. 

“So you’ve seen at previous, low-drag tracks we’ve trimmed our wing away. This one’s designed for this downforce. Both of those together are useful and those are items that when we make them, we re-make them lighter, so it’s helping with getting weight out of the car.

“We’re always trying to get weight out of the car, we were still overweight. And it seems to be working reasonably well.”

Track temperatures reached more than 50 degrees Celsius at times on Friday and Shovlin admitted the conditions likely boosted Mercedes’ performance after the team was hampered by tyre warm-up issues last time out in Italy. 

“In Imola we were struggling with [tyre] warm-up, the big thing here is overheating,” he explained. “Whether that’s shifted us in the right direction I don’t know.

“But we won’t get excited about where we are here, we know that we should have improved the car, but we know we’ve got a lot of work to do.”

Asked if the team is back in the fight at the front of the grid, Shovlin said: “We’re not going to say that just yet. 

“Obviously getting into Q3 is the minimum expectation for this team but we know that we had a long road to go along and we’re just trying to do that step-by-step.”

Mercedes drivers not ‘getting too carried away’ 

Russell, who sits fourth in the drivers’ championship, described Mercedes’ day as the “most productive Friday we’ve had” but conceded the team do not fully understand their strong start to the weekend. 

“We don’t really understand it to be honest, why we sort of hit the ground running,” he said.  

“We always knew ahead of this weekend that the conditions should suit us better because we have been struggling a lot with tyre warm-up. 

“But this is the first real hot race of the season, so for sure that’s played a big factor. The car is working well, but it’s only Friday, so not getting too carried away.”

In the other car, Hamilton ended the day fourth, two-tenths off his young Mercedes teammate, who he also trails by 21 points and three places in the championship. 

The seven-time world champion downplayed the impact of the new parts Mercedes have brought to Miami and stressed it is too early in the weekend to draw any firm conclusions. 

“It’s just practice, so everyone’s doing something different in practice, I don’t think everyone’s shown their true pace,” he said.  

"It feels similar to me. I think we seem to be quicker here and later on they were explaining to us we definitely have improved in some way. 

“I’m not sure where that is, but there are definitely positive elements to take from today.” 

Hamilton admitted he is currently struggling to tame Mercedes’ troublesome W13 as Russell continues to hold the early upper hand at the Brackley-based squad. 

“I’m still struggling with the car, George looked great out there, but we’re trying a lot of different things but we’ll converge and hopefully improve.”

Despite making visible improvements, both Mercedes drivers reported that the team have not been able to completely cure the high-frequency bouncing that has plagued their car in 2022. 

“I think we know that it will always be there, but maybe it’s working at a lower [ride-height] range compared to where we were previously,” Russell explained. 

“On the high-fuel run I was feeling it and it didn't seem to be any better, but if we can manage to do that with the car lower to the ground then obviously we seek the rewards. 

"But as I said, you generally have races that go in your favour, some races that go against you. I think Imola obviously wasn’t a strong circuit for us, but so far from what we see, the car is working well around Miami.”