Lando Norris set the pace in the final Emilia Romagna Grand Prix Formula 1 practice session at Imola, as much of the F1 field struggled badly with the new C6 tyre.
It was the third successive McLaren 1-2 of the weekend, but the session was far from straightforward - and promised a sterner challenge against McLaren at least on the harder tyre.
The C6 - the new softest tyre in Pirelli's range introduced this year and debuting this weekend - looked fragile but at least the obvious for qualifying trim on Friday, but this was no longer the case in the hour of running on Saturday morning, suggesting a potential qualifying headache.
After big steps in pace early in the session on the C5 mediums, only some drivers and teams were able to continue that positive pace trend after the switch to C6s, and even those who did - like pacesetter Norris - seemed to find them something of a handful.
Norris had a big trip through the gravel on the inside of the Tamburello chicane and told McLaren he was finding the balance worse, even after using the C6 for the first sub-1m15s lap of the weekend - a 1m14.897s.
Team-mate Oscar Piastri had a generally untidy run through the mediums, and had to bail out of his first soft-tyre push lap after overcooking the entry to Acque Minerali 2, but kept at it and ultimately joined Norris in the 1m14s range.
Red Bull's challenge?
Red Bull looked to have taken a big overnight step as Max Verstappen showed up the McLarens on the session's early runs on the C5 mediums, eking out more and more laptime out of it until he found himself with a 1m15.078s - better than Friday's C6 benchmark.
Yet Verstappen - who feared this weekend's softer allocation would hurt Red Bull - couldn't better than that on the C6s, so ended the session 0.181s off the pace in third.
Team-mate Yuki Tsunoda was another driver - out of a total of five - to set his best time of the session on the mediums, though he was a full 1.2s off down in 17th.
How the others got on
Rookie Kimi Antonelli was best of the rest behind the 'big three', having struggled to get a representative lap in on mediums but stringing one together on softs - though he was still half a second down on Norris's McLaren.
His team-mate George Russell - four places down in eighth - had to rely on his medium time, as a dip into the gravel undid his first soft-tyre push and he never found the pace on that compound.
Slotting in between them was the lead Ferrari (Charles Leclerc), the lead Williams (Carlos Sainz) and the lead Racing Bulls (Isack Hadjar).
Hadjar flashed an impressive turn of pace early in the session but - like many - couldn't find a step on the soft tyre.
His team-mate Liam Lawson had a big spin - but a less consequential one - in the same spot where Hadjar had brought out the red flag on Friday, exiting the Tamburello chicane.
The top 10 was completed by Sainz's team-mate Albon and Leclerc's team-mate Hamilton, who asked Ferrari to check for floor damage after riding the exit kerb at Rivazza 2 hard late in the session.
Results
1 Lando Norris (McLaren) 1m14.897s
2 Oscar Piastri (McLaren) +0.100s
3 Max Verstappen (Red Bull) +0.181s
4 Kimi Antonelli (Mercedes) +0.502s
5 Charles Leclerc (Ferrari) +0.554s
6 Carlos Sainz (Williams) +0.560s
7 Isack Hadjar (Racing Bulls) +0.611s
8 George Russell (Mercedes) +0.765s
9 Alex Albon (Williams) +0.835s
10 Lewis Hamilton (Ferrari) +0.890s
11 Fernando Alonso (Aston Martin) +0.922s
12 Ollie Bearman (Haas) +1.047s
13 Lance Stroll (Aston Martin) +1.078s
14 Liam Lawson (Racing Bulls) +1.080s
15 Pierre Gasly (Alpine) +1.093s
16 Gabriel Bortoleto (Sauber) +1.149s
17 Yuki Tsunoda (Racing Bulls) +1.213s
18 Franco Colapinto (Alpine) +1.313s
19 Nico Hulkenberg (Sauber) +1.341s
20 Esteban Ocon (Haas) +1.490s
