Max Verstappen took up his perennial place at the head of the timesheet in first practice for the Italian GP at high-speed Monza - but Ferrari finished right behind to begin the biggest weekend of their year in encouraging style.
Red Bull's Verstappen set the pace on 1:22.657 but his advantage was only 0.046 seconds from Ferrari's Carlos Sainz, with Sergio Perez a further tenth back in third.
Verstappen is chasing a record 10th race win in succession on Sunday.
Charles Leclerc was fourth in the second Ferrari, ahead of Mercedes' George Russell and Aston Martin's Fernando Alonso.
Lewis Hamilton, fresh from the announcement on Thursday of his new two-year deal to stay in F1 at Mercedes, opened up his weekend with the eighth-quickest time in the other Mercedes.
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Although the session was low on dramatic incident around the famous old circuit, Williams' in-form Alex Albon did well to avoid an accident when he ran wide through the gravel on the high-speed exit of the Ascari chicane.
Albon collected it up well and went on to finish 10th quickest, with the improving Williams team appearing set for a strong weekend given their car is especially strong in a straight line.
The Italian GP is the second race weekend of the year where F1's trial Alternative Tyre Allocation (ATA) system is in place.
While the headline change affects qualifying - where teams have to run set compounds in each knockout segment of the hour-long session - it also sees fewer tyres brought to the weekend in total.
When the ATA system rules were first trialled at the Hungarian GP in July, teams inevitably ran fewer sets of new tyres during Friday practice - and so proved the case in the opening session here too.
The top five on the timesheet all used the same hardest compound throughout the hour, with the best lap times therefore set a little earlier in the session than normal.
Meanwhile, although the team itself is based in Switzerland, the Monza weekend is also a home race of sorts for the Alfa Romeo-sponsored outfit. But it proved a rough start for them with both their cars kept in the garage in the early stages by suspected anti-stall issues.
On his return to the track, Valtteri Bottas then complained over the radio that the C43 was "undriveable". However, the situation seemed to have improved by the end of the hour as the team's drivers each completed 17 laps apiece.
Sky Sports F1's live Italian GP schedule
Friday 1 September
2pm: F3 Qualifying
2.45pm: F2 Qualifying
3.40pm: Italian GP Practice Two (session starts at 4pm)
5.15pm: The F1 Show
Saturday 2 September
8.20am: F3 Sprint Race
11.15am: Italian GP Practice Three (session starts at 11.30am)
1.10pm: F2 Sprint Race
2.10pm: Italian GP Qualifying build-up
3pm: Italian GP Qualifying
4.45pm: Ted's Qualifying Notebook
Sunday 3 September
7.10am: F3 Feature Race
8.15am: F2 Feature Race
12.30pm: Grand Prix Sunday: Italian GP build-up
2pm: THE ITALIAN GRAND PRIX
4pm: Chequered Flag: Italian GP reaction
5pm: Ted's Notebook
Watch the whole of the Italian Grand Prix, which is the last European race of the season. live on Sky Sports F1 this weekend. Stream F1 on Sky Sports with NOW for just £26 a month for 12 months. Cancel anytime