McLaren heads the constructors’ championship with four rounds to run, holding a 29-point advantage over Ferrari.
The Scuderia has won the last two events, with Charles Leclerc leading a one-two in the United States Grand Prix and Carlos Sainz a one-three for the squad in Mexico last weekend.
It has seen Ferrari overhaul Red Bull Racing in the standings, having trailed it by 71 points after the British Grand Prix.
“We always knew that Ferrari were going to be a threat,” Piastri noted of the constructors’ championship battle.
“Since Monza, basically, I think they’ve had a very, very quick car, just some of the weekends the results haven’t shown it.
“So for us, it’s not been a huge surprise that they’ve been as quick as they’ve been in the last few weekends, especially.
“We’ll see if that run continues, but we need to expect a fight, definitely.
“It’s going to be an exciting end to the year in both championships.”
Piastri’s McLaren team-mate, Lando Norris, remains second in the drivers’ championship, 47 points back from Max Verstappen.
The Brit took 10 points out of that advantage in Mexico City, though needs more big weekends if he’s to seriously threaten for the title, a point acknowledged by Piastri.
“It’s possible, you know, it’s certainly not an easy task,” he reasoned.
“In some ways, it’s up to both drivers.
“Lando can’t just win every race and have Max finish second, because Max will still win [the championship], so it depends a bit on the result.
“It’s obviously a very tight fight with the top three teams, and Mercedes occasionally now.
“The swing either way can still be quite big at the moment.
“I think it’s possible [for Norris to win the championship]. It’s going to be tough, but I think it’s doable.”
Having only taken his first F1 win in Miami, Norris also won the Dutch and Singapore Grands Prix.
He finished a charging second in Mexico last weekend, closing on race winner Carlos Sainz, and has eight other podiums to his name this season.
Piastri has claimed two wins and five other podiums in 2024, this most recent a third place in Singapore.
In the United States, a difficult car limited his chances, while a qualifying mistake last weekend hurt him come the race.
“I think Austin, we had a car that was quick but very, very difficult to drive,” the Australian explained
“In qualifying especially, was tough to get the most out of it.
“In the race, just going a bit slower with the lap times, maybe a little bit easier to get pace out of it.
“I was much happier in Mexico, which obviously the results don’t reflect,” he added.
“Felt much more comfortable, and kind of made qualifying even more of a shame, really.
“I would rather, in some ways, have a weekend like Mexico, where I’m comfortable, at least, and knowing that I made a mistake, rather than a bit more in Austin, where just struggling to get the most out of car.”
This weekend’s Sao Paulo Grand Prix is another Sprint event, leaving drivers and teams just an hour of practice before competitive running begins.
Free Practice 1 begins in Interlagos at 11:30 on Friday morning (01:30 AEDT Saturday).
