Penalties saw Lewis Hamilton start at the back of the grid for Saturday’s sprint race and in 10th place for Sunday’s main event in Sao Paulo, but the Mercedes driver finished fifth then first across those races to narrow the gap to championship leader Max Verstappen.
Verstappen started second in Sunday’s grand prix but quickly overtook Hamilton’s teammate Valtteri Bottas, leading for much of the race until Hamilton’s impressive performance saw him overtake the Dutchman with 12 laps remaining.
From there, defending champion Hamilton secured the victory to reduce the deficit to Red Bull’s Verstappen to 14 points with three races left this season.
“It was unraceable. We put up as big of a defence as we could; Max did his best and raced hard.
“Their straight-line speed is really impressive, that new engine. Max can’t defend against that, any other driver had to get within 0.4 seconds to get near to an overtake.
“If Mercedes were within 0.9 seconds, they could be in the braking area at the end of the straight. That’s a potent weapon with fast tracks coming up.”
Red Bull have expressed concern over whether Mercedes’ rear wing in Brazil conformed to regulations, with Verstappen fined for touching Hamilton’s vehicle on Friday.
“We won’t be protesting at this race,” Horner said. “It’s important to understand where the speed came from. They’ve got a new engine and Monaco [Grand Prix] levels of downforce.
“When [Hamilton] passed Max, he was 30kph quicker on that lap. It’s something we need to understand and it’s down to the FIA to police the sport. We trust their tests.
“We have our suspicions, and I still think there is something going on with the main plane [of the rear wing] giving them top speed. There is clearly something going on.”
Seven-time champion Hamilton is bidding to go one clear of joint-record holder Michael Schumacher by triumphing this season, while the Briton’s rival Verstappen is seeking his first Formula 1 title.
Next up is the Qatar Grand Prix on Sunday, followed by events in Saudi Arabia and Abu Dhabi.