Mercedes admits it is at a loss as to where its pace came from as Lewis Hamilton topped the first two practice sessions for the Las Vegas Grand Prix.
Hamilton led an all-British top-three across both practice sessions, with Mercedes team-mate George Russell second in FP1 and behind the McLaren of Lando Norris in third later on.
Having fallen back following three wins from four races at the start of the summer, the times are promising for Mercedes – although Russell conceded no-one knows quite how the car delivered the pace.
“Yeah, incredible day. I'd love to tell you why, to be honest, we are scratching our heads a little bit, why it was so, so positive,” he said.
“Obviously, it was only practice. Lewis did a really great job out there as well. He's been really on it since lap one, but the car has just been working. But you know, we're on a street track. It's really dirty.
“It's getting faster and faster every lap. Because we were fast today, it doesn't necessarily mean we're going to replicate it tomorrow, when the track will be probably three seconds faster. So, pleasantly surprising.”
The fact the Las Vegas Strip Circuit runs on the busy streets of the city meant plenty of dust was sitting on the surface when running began.
Given Mercedes’ ability to deal with the conditions helped them to set competitive pace, team principal Toto Wolff is hoping plenty of traffic will once again deposit dust onto the track before it is closed off again for final practice and qualifying.
“I think we are dirty track champions,” he said.
“FP1 is always great and then the moment the grip kicks in, we've seen that the performances deteriorate. Having said that, I think the gap was pretty big. It's the biggest that we've seen so far in FP1, so we've got to spray some dust for all the sessions tomorrow, in qualifying or something.
“But I don't believe this kind of advantage to the other teams is going to last. I would very much hope that we're not falling behind like we did in the past on some of the tracks, but remain competitive, fight in the front.”
Russell echoed the sentiments of Wolff and feels other teams may have also been holding something back.
“It's definitely not a fear. I think the perception of us losing performance is maybe not quite fair,” he said, when asked if he was fearful Mercedes could be pegged back.
“I think it's more of a function that our competitors don't use their high power. They might be running a bit more fuel than us on a Friday, so they're kind of historically, they've been sandbagging a little bit more, and when they take it off they go into their normal position.
“There's a possibility that will happen again tomorrow, but the gap we showed this morning and this evening has been pretty substantial.
“But I'm sure the other rivals are going to work hard overnight and close that gap, but I just hope we can continue the form.”
After Wolff’s mixed messaging over an extract from a Mercedes book when he suggested Hamilton’s “shelf life” may be expiring, the seven-time world champion would have been pleased to set the early pace in Vegas.
“It is the first time I’ve had a day like that, I think this year. So, the car was feeling really good in P1, in P2 less so,” he said. “So we have got some work to do overnight.
“It is difficult to know exactly where we are or why we are where we are, but I really enjoyed driving the track and we will see whether the car is still the same tomorrow.
“I’m feeling good in myself, yeah, I knew coming into this weekend that is not my driving. So I have just got to work hard overnight not to make big change, and hopefully get some good rest tonight and come back strong tomorrow.”
