Lando Norris was fastest in his upgraded McLaren from new Formula 1 world champion Kimi Antonelli in first practice at the Sao Paulo Grand Prix.
McLaren have not fought for victory in recent races but could be contenders in Brazil this weekend as Norris showcased their pace by beating Antonelli by 0.082s.
Despite most teams focusing on their 2027 cars, McLaren have brought a new front wing, rear wing, beam wing and floor furniture to the car, and it appears to have made an immediate impact.
Four different teams were in the top four as Red Bull's Max Verstappen was third at 0.236s off the pace and Ferrari's Lewis Hamilton was fourth, 0.324s behind Norris.
George Russell, who questioned the frequency of his "atrocious luck" this season on Thursday, was fifth in first practice, just ahead of Red Bull's Isack Hadjar.
Russell has a five-grid place penalty for a new internal combustion engine, so will start no higher than sixth in Sunday's race at Interlagos.
Mercedes can win the Constructors' Championship this weekend if they outscore Ferrari by three points, or more, with Antonelli already crowned world champion last weekend following his podium in Mexico.
Antonelli is honouring three-time F1 world champion Ayrton Senna with a special helmet in tribute to the Brazilian.
Herta qualifies for F1 super licence - will he get 2027 Cadillac seat?
Six replacement rookies ran in first practice as the teams continue to tick off the mandatory requirement that a rookie must run in at least two practice sessions across the season in both of their cars.
There was plenty of attention on Formula 2 driver Colton Herta as he, crucially, completed 100km around Interlagos to gain another super licence point.
That takes him to 40 super licence points overall which is the minimum a driver needs to be eligible to race in Formula 1 full-time.
Although Valtteri Bottas signed a multi-year contract, which started at the start of 2026, his future at Cadillac is uncertain after a difficult season in comparison to team-mate Sergio Perez.
Cadillac are seemingly keen to have an American driver in one of their seats, and now have the option to replace Bottas with Herta.
Formula 2 championship leader Rafael Camara made his F1 debut as he replaces Esteban Ocon at Haas this weekend, as the latter has been dropped by the team for the remainder of the season following a dispute in Mexico.
Camara, who already has been confirmed to drive for Haas full-time in 2027, was 18th and had a clean session.
Alpine junior Gabriele Mini was the fastest replacement rookie in first practice in seventh with McLaren's Leonardo Fornaroli in 11th.
Williams' Luke Browning was limited to just 12 laps due to an issue and Ferrari's Dino Beganovic, who replaced Charles Leclerc, spent most of the session in the garage due to a floor change.
British teenager Freddie Slater suffered more misfortune as a suspected gearbox issue saw him come to a halt in the middle sector in his Audi. Last Friday in Mexico, Slater's track time was cut short because of technical problems.
Friday November 6
6.45pm: Sao Paulo Grand Prix Practice Two (session starts at 7pm)
8.15pm: The F1 Show
Saturday November 7
2.15pm: Sao Paulo Grand Prix Practice Three (session starts at 2.30pm)*
5pm: Sao Paulo Grand Prix Qualifying build-up
6pm: SAO PAULO GRAND PRIX QUALIFYING
8pm: Ted's Qualifying Notebook
Sunday November 8
3.30pm: Grand Prix Sunday: Sao Paulo GP build-up
5pm: THE SAO PAULO GRAND PRIX*
7pm: Chequered Flag: Sao Paulo City GP reaction
8pm: Ted's Notebook
*also on Sky Sports Main Event
Formula 1 is in Brazil for the final leg of the triple header with the Sao Paulo Grand Prix this weekend, live on Sky Sports F1. Stream Sky Sports with NOW
