Formula 1 teams have been advised that race control has changed its stance on track limits following the opening day of the Portuguese Grand Prix.

Ahead of the weekend, FIA race director Michael Masi confirmed that officials would be monitoring the exits of Turn 1, 4, and 15.

Following Friday’s two 60-minute practice sessions, the exit of Turn 5 has now been added to that list.

Note 21.3 in Masi’s updated notes to teams states that “the track limits at the exit of Turn 5 are defined as when no part of the car remains in contact with the red and white kerb.”

Turn 5 is the left-hand hairpin at the end of the back straight, which leads into a left-hand kink on the brow of a hill.

The stance on track limits at the corner is consistent with that applied at Turn 1 and Turn 4, while at Turn 15 – which is easily full throttle – the limits are defined as the white lines at the edge of the racing surface.

In Free Practice 2, a total of 30 laps were deleted by officials.

Of those, 12 were for exceeding the limits at Turn 4, and the balance at Turn 1.

It was a similar case in opening practice, when 17 laps were cancelled for exceeding limits at Turn 4, and 18 at the opening corner.

Mercedes topped both sessions on Friday, Valtteri Bottas leading the way in the opening session before Lewis Hamilton proved fastest in the afternoon.

Practice continues with a further 60 minutes of running from 21:00 AEST tonight, and qualifying then to follow.