The 20-year-old lapped with a best time of one minute 15.775 seconds on the softest C5 tyres, only 0.264 off regular race driver Valtteri Bottas's Tuesday pace on the same compound, and did 128 laps.
"Today was incredible. Being a part of this team, even just for this day was very special for me," said the Russian, whose billionaire father tried unsuccessfully to buy the Force India (now Racing Point) team last year.
"It's every young driver's dream to drive a car like this and today mine came true."
Thai driver Alexander Albon was second fastest for Toro Rosso with Italian Antonio Fuoco, testing for Ferrari, third on the timesheets.
The junior drivers were in a majority, with Ferrari's race regular Charles Leclerc mostly tyre testing for Pirelli along with Racing Point's Lance Stroll.
(Reporting by Alan Baldwin, editing by Toby Davis)
