After favourites Ferrari fired up the fans in the first session at a sweltering Monza, with Charles Leclerc leading teammate Lewis Hamilton in a potent one-two at their home 'Temple of Speed", Russell surged to the top in second practice at the super-fast circuit.
His lap of 01:22.559 seconds was 0.120 quicker than Leclerc, second in session two, and served a notice of intent ahead of a race he needs to win to close the 59-point gap to championship-leading teammate Kimi Antonelli.
Antonelli, who is set to start from the back of the grid due to engine penalties, was third fastest in the second session and 0.141 off the pace with McLaren's reigning world champion Lando Norris fourth, Hamilton fifth and McLaren's Oscar Piastri sixth.
Norris has won the last two races and will be chasing a hat-trick on Sunday.
Ferrari, who last won at Monza with Leclerc in 2024 and are celebrating 30 years since Michael Schumacher's first Italian Grand Prix win, have brought an engine upgrade to Monza and the circuit's characteristics should suit their car.