Australian McLaren driver Oscar Piastri notched a sixth place in the second practice and 11th in the first run.
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 one minute and 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.
Leclerc had clocked a best time of 1:23.008, 0.173 quicker than Hamilton, in the first practice in front of tens of thousands of fervent tifosi.
"There's still some work ahead of us as our competitors look strong, but so far the feeling with the car was solid," Leclerc said.
Hamilton said the upgraded power unit was a step in the right direction.
"We made some changes through the day and there are positive things to take from the sessions, but it was still difficult to get the most out of the car and put a complete lap together," added the seven-time champion.
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 and Hamilton fifth.
Norris has won the last two races and will be chasing a hat-trick on Sunday.
"The pace isn't where we need it to be right now," said the Brit.
"Oddly, we need to find performance in the corners where we expected to be strong, while we're a bit better than expected in the ones we thought would be difficult. It's very tight at the front and the group behind isn't far off either, so we'll work overnight to find gains, but it's going to be tough."
Antonelli, who has won six races so far to Russell's two, said it had been different to the usual Friday and the focus had been on long runs and gathering data.
"It was interesting in the long run today running behind other cars to see what they were doing differently, where they were deploying compared to us," he said.
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.
Russell, who won the Melbourne Grand Prix back in March, is level on points with Hamilton after 12 rounds and was third fastest in first practice.
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