Red Bull's Vettel led Hamilton by 0.036 seconds in afternoon practice Friday, while Hamilton and McLaren teammate Jenson Button finished 1-2 in front of Vettel in the morning session.
"It's a track that traditionally doesn't suit us, but we were happy with the car today," said Vettel. "McLaren looks very quick in particular and the ones to beat this weekend, but it's very difficult to judge on a Friday."
Michael Schumacher of Mercedes, a five-time winner at Monza when he was with Ferrari, might also be poised for a resurgence after placing third in the afternoon, while Ferrari struggled in both sessions at its home race.
"It's always a special feeling to be here in Monza," said the 42-year-old Schumacher, who hasn't won a race since he came out of retirement last year. "It certainly looks good in terms of my position today and I'm pleased with that but we will only find out tomorrow what it is really worth."
Vettel became the youngest winner in F1 history when he won at Monza in 2008 at 21 when he was with Toro Rosso, but his fourth-place finish last year was Red Bull's best result at the circuit.
Red Bull is eager to improve its record this weekend because Vettel has won seven of the 12 races thus far this season and could wrap up a second consecutive championship at the next race in Singapore.
Hamilton has also never won at the historic track north of Milan, with his best finish a second-place result during his rookie season in 2007. The British driver has two wins this season but is only fifth in the standings following a series of accidents that have marred six of his races.
Hamilton had a chance at leading both practices, but he ran into traffic in the afternoon, slamming on his breaks after nearly running into Jaime Alguersuari's Toro Rosso just as he was finishing a fast lap.
Hamilton also reported a problem with his clutch late in the second session.
Schumacher, meanwhile, had an up and down day. He was fortunate to avoid the wall after losing control midway through the 180-degree Parabolica turn during the morning, then had to back off the throttle suddenly during the middle of the same turn in the afternoon to keep the car from hitting the gravel again.
"In terms of the character of the circuit, we are usually good on braking and traction, and there are not so many of the medium and high-speed corners in which we have not been so strong this year," Schumacher said.
Fernando Alonso won this race with Ferrari last year, but the local fans — more affectionately known as "tifosi" — might not get such a treat this year.
Alonso was only seventh in the morning after his session was cut short by an apparent cut left rear tire, and he finished fifth behind Massa in the afternoon.
Alonso's British GP win in Silverstone in July was Ferrari's only win this year, as the Italian team continues to struggle with the new Pirelli tires.
Tires are key in Monza, which is the fastest track in the sport, with average speeds of 250 km/h and top speeds of 340 km/h.
The track's layout — slow corners followed by long, high-speed straights — means drivers should also get optimal use out of their drag reduction systems (DRS) — adjustable rear wings — and the KERS power boosts.
Qualifying is scheduled for Saturday, followed by the race Sunday.