was recruited from Scuderia Toro Rosso in 2019 to replace the outgoing Tim Goss, and was named as the MCL35's lead designer. In October 2019 team principal Andreas Seidl stated very little of the MCL34 would be carried over to the MCL35, with the aim of the closing the gap to the top three teams to under one second. Lando Norris stated that one of the team's major areas of focus would be to improve the MCL35's cornering ability.
Aside from minor upgrades, 2020-specification cars were meant to be kept largely unchanged for the 2021 season. However, McLaren received special permission—subject to inspection from the FIA—to make modifications to the chassis that would allow the MCL35 to accommodate the new Mercedes engine as the team had signed an agreement with Mercedes before the decision for all teams to keep using their 2020 cars was made. This requirement led directly to Formula One's adoption of a token-based system for 2021 vehicle development.
Switch from BP-Castrol to Gulf fuels and lubricants
Gulf are due to partner and provide McLaren for fuel and lubricant products ending the BP and Castrol partnership as a team's official fuel and lubricants partner after 3 and a half years.
Season summary
Prior to the beginning of the season, the team established their aim to defend their status as 'best of the rest' – fourth place in the Constructors' Championship behind the current leading trio of Mercedes, Ferrari and Red Bull – and close the gap to those respective teams. In preseason testing however, Racing Point, whose car strongly resembled the 2019 Mercedes car, was very quick compared to the other midfield teams, and caused McLaren to be less than optimistic about their chances to secure fourth place. The season was heavily disrupted by the COVID-19 pandemic, leading the reorganisation of the calendar.
Opening rounds
McLaren used a new floor, diffuser, and brake ducts at the Austrian Grand Prix as well as a tweaked front wing. Norris qualified in fourth and was promoted to third after a penalty was given to Lewis Hamilton, while Sainz qualified in eighth. This was McLaren's best grid start since 2016. After Norris lost positions in the opening laps to Hamilton and Alexander Albon, both McLarens ran comfortably in the top ten for the remainder of the race. In the closing laps, Hamilton collided with Albon and was given a five second penalty. Norris, running in fifth, was required to close the gap between himself and Hamilton to under five seconds in order to finish in the top three, overtaking Sergio Pérez and setting his first fastest lap on the last lap of the race in the process. Sainz finished in fifth after also overtaking Pérez. This was McLaren's second podium in three races after the 2019 Brazilian Grand Prix, in sharp contrast to their previous gap of 118 races. McLaren used a new chin spoiler design during the Styrian Grand Prix. Sainz qualified in third, the best outright qualifying position for McLaren since 2014. Norris qualified in sixth but was demoted to ninth after a penalty from free practice was applied. Norris would go on to finish fifth after overtaking both Racing Point drivers on the final lap, while Sainz would finish ninth and set the fastest lap and a new track record in the process. McLaren used a new engine cover and T-wing design during the Hungarian Grand Prix. McLaren had a poor showing in Hungary compared to the Austrian rounds. While Sainz did manage third in second practice, McLaren would only manage to qualify eighth and ninth. Both Sainz and Norris dropped positions while changing tyres on lap four, being held up by traffic in the pit lane. Norris could only recover to thirteenth after being passed by Charles Leclerc. Sainz finished tenth, and was later promoted to ninth after Haas driver Kevin Magnussen received a penalty. At the British Grand Prix, McLaren removed the T-wing and reverted their engine cover design to the pre-Hungarian version, while using a new front wing, rear wing, and floor design. Norris and Sainz would go on to qualify fifth and seventh respectively.
