Formula 1 enters the final countdown to determine who will win out in the titanic world championship tussle between Lewis Hamilton and Max Verstappen, Mercedes and Red Bull, over the next month and a half.
A captivating 2021 campaign concludes with five races in the space of six weeks until December 12, a run that sees the sport visit three different continents and race at two new venues.
The first of those five rounds, the Mexico City Grand Prix, takes place this weekend live on Sky Sports F1.
Verstappen leads Hamilton in the Drivers' Championship by 12 points, whereas it is a 23-point advantage for Mercedes over Red Bull in the Constructors'.
"It's session by session, race by race," said Red Bull boss Christian Horner to Sky F1 when speaking about the battle to be on top against Mercedes.
"You've just got to keep doing the basics well. We've got to make sure we're reliable, that the pace is there, that we're responding to whatever challenges are put on us.
"Five to go now and there's a couple of races that are going to be strong for us. We know a couple that will be strong for these guys [Mercedes], so it's going to be really tight."
One of those races that has historically been strong for Red Bull is this weekend's venue, the Autodromo Hermanos Rodriguez in bustling Mexico City. Located 2,250 metres above sea level, the thinner air places different demands on engines, particularly the turbo component, which has suited Mercedes' rivals better in the past.
However, as underlined as recently as the Circuit of the Americas a fortnight ago, the formbook of past years has counted for little in this most topsy-turvy of championship battles.
"Mexico was traditionally a track that was difficult for us but this season everything can change," said Toto Wolff, Mercedes' team principal.
"We have seen our strong ones and they haven't [been] and vice-versa. So I think it's really race by race, keeping the spirits up."
Mercedes' seven-year reign as Formula 1's world champions has not been without sustained external challenge at times, most notably from Ferrari, but Red Bull appear set to be the first team to take them to the wire in the hybrid-turbo engine era.
"We have had tough fights with Ferrari in 2018 and 2019, and we won seven times in a row. But that is no comfort whilst you are in a championship that's hard, the history has no relevance," added Wolff.
"It's hard but we have fun, we are enjoying it."
Sky Sports F1's Mexico City GP schedule
Thursday
10pm: The F1 Show Live*
11pm: Drivers' Press Conference
Friday
5pm: Practice One Live (Session starts at 5.30pm)
8.45pm: Practice Two Live (Session starts at 9pm)
Saturday
4.45pm: Practice Three Live (Session starts at 5pm)
7pm: Qualifying Build-up Live
8pm: MEXICO CITY GP QUALIFYING LIVE*
9.45pm: Ted's Qualifying Notebook
Sunday
5.30pm: Grand Prix Sunday Live
7pm: THE MEXICO CITY GRAND PRIX LIVE*
9pm: Chequered Flag Live*
10pm: Ted's Notebook Live
*simulcast on Sky Sports Main Event