The Leclerc laps that has Red Bull on alert for the Japanese GP

A red flag in Free Practice 1 and the arrival of rain in the second session meant the usual clues Formula 1 teams usually find about their performance were hard to come by on Friday of the Japanese Grand Prix.

Drivers largely spoke vaguely about where they felt they would end in the pecking order, but it was Ferrari's Carlos Sainz who dared to draw a conclusion, based on data drawn only from FP1.

"FP1 was a bit closer to the Red Bulls than I anticipated or expected, so positive signs from five months ago [in Japan] to now," said Sainz.

"Still obviously, it’s FP1 and you don’t know what fuel loads and engine modes they’re running.

"Last year we were eight-tenths off in qualifying and here, to be two-tenths off in FP1 is a good feeling and a good starting base.

"But they are going to be difficult to beat this weekend.".

How is the field stacking up?

From the small data set, Red Bull's interest was piqued by a run from Charles Leclerc in FP1 on the Hard compound Pirelli tyres.

"That run from Leclerc was a bit annoying, well, not annoying but he was really fast," said Marko.

"We have to see how much fuel he had on-board for the run.

Leclerc's run, at the end of the session was only three laps, compared to four for Verstappen, but the Monegasque was still nearly half-a-second to a second faster than the World Champion in his upgraded RB20.

Both drivers used scrubbed tyres, with a similar age on the rubber, as Lewis Hamilton enjoyed what he called the "best session of the year" for Mercedes.

He was fifth in FP1, with a long-run on the Soft tyres but could not quite show the same pace Leclerc or Verstappen did, indicating that the Mercedes is well-behind the top two.

Over the course of the seven-lap stint, Hamilton also suffered a drop-off of 1.8s, as the table below charts the three drivers.