Sebastian Vettel and Ferrari set the pace on the final day of in-season testing, but it was Lando Norris and Robert Kubica who stole the show at the Hungaroring.
Vettel and team-mate Kimi Raikkonen shared the Scuderia running after Charles Leclerc topped the timesheets on Day One, with the 2017 championship leader setting a best time of 1:17.124 in the morning session.
The supersoft tyre benchmark was less than a second shy of his pole time during the Hungarian GP qualifying.
But with Raikkonen finishing third, it was British rookie Norris who split the title-winning duo for McLaren as the youngster made an instant impression on his debut.
The 17-year-old, currently impressing in the European Formula 3 Championship, enjoyed a remarkable first official day in an F1 car as he produced a lap of 1:17.384.
While Norris's attention-grabbing best time was set on a compound not available during the weekend's Grand Prix, the ultrasofts, it was still McLaren's fastest time over the entire week in Budapest.
"Lando has impressed us all with his maturity, professionalism and speed, and has got to grips very quickly with the car," said team boss Eric Boullier. "He's certainly an asset to our test driver line-up - not to mention a potential star of the future."
Kubica returns with an innings of substance
But the top three were perhaps all overshadowed by Kubica, who made an emotional yet assured return to Formula 1.
Kubica, driving a contemporary F1 car for the first time since suffering career-threatening injuries in a rally crash six years ago, finished fourth for Renault and was consistent throughout his 142 laps, a tally beaten by only one other driver.
His best time of 1:18.572 - set on ultrasoft tyres in the afternoon - was almost two seconds quicker than Renault development driver Nicholas Latifi's benchmark from Day One, while it was only a tenth of a second shy of Jolyon Palmer's fastest Hungarian GP qualifying effort.
Picture special: Kubica returns
The Pole's performance, displaying endurance and speed in a test which Renault considered crucial for his future, could open the door to a full-time return to the sport in 2018.
Cheered on by adoring fans in the grandstands, the 32-year-old steadily improved as the day progressed and completed a full race distance by lunch, running seventh at the time of the break.
Kubica, an F1 race winner with Sauber in 2008, then marked a century of laps early on in the afternoon session before Renault fitted the ultrasofts in the final hour when he set his quickest time of the day.
"After today, it's too early to say what the next step might be," said Kubica afterwards. "I would like more opportunities but the reality is that l don't know. We will have to wait and see."
How did Kubica's fastest laps compare?
Kubica's personal best of 1:18.572 was a lot quicker than Latifi's 1:20.302 on Day One of testing - although it was set on ultrasoft tyres.
Kubica's best time on supersofts, a compound available to both Palmer and Nico Hulkenberg at the Hungarian GP, was a 1:18:952.
Here's how it compared to the Renault driver's times over the weekend...
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