Max Verstappen - who can score a record-breaking 10th grand prix victory in succession this weekend - was only fifth fastest but found traffic on his soft tyre run, while team-mate Sergio Perez was third but ended his session in the gravel at Parabolica.
In a bid to avoid the chaotic scenes of recent years at Monza, the FIA has implemented a minimum lap time designed to stop drivers from crawling at low speed in order to create space for a hot lap.
FP3 will get under way at 11:30 BST with qualifying following at 15:00 BST.
A reminder, Q1 must be completed on hard tyres and drivers will take several laps to get heat into their tyres. But then, the tow is vitally important, so expect plenty of traffic problems!
One driver beyond the usual suspects to watch out for is Albon. The Williams driver has been particularly competitive on the hard and medium compounds, meaning he is a strong contender to reach Q3.
Rosberg has described the policing of track limits as "tedious". It is, however, a case of the rules being the rules, and the track limits being the track limits.
Good news for Perez fans, after completing an engine change, the Red Bull mechanics appear to have his car all but ready to take part in Q1 without delay!
You may have noticed that the scenery has changed at Monza this year with many trees missing. There are, in fact, around 10,000 trees missing after recent storms caused many to fall. The full story is here...
Red Bull has been working since FP3 to repair an oil leak it discovered on Perez's car in the closing stages of that session. Following a crash in FP2 on Friday, it is another weekend that - so far - could have gone far better for the Mexican.
So far this weekend, we have seen traffic play a significant part in the sessions. As this is again supposed to be the case in qualifying, the FIA has acted to set a minimum lap time that drivers must adhere to
Before we go any further, time for a little bit of housekeeping. This weekend is running to the alternate tyre allocation system, which means drivers must use the hard compound in Q1, medium in Q2 and softs in Q3.
Small shoutout to Lawson in 12th, who beat Tsunoda by 0.001s in that session. Given he's only had three and a bit days in that car, that's an impressive feat.
Sainz has been shown the black and white flag for impeding Piastri, as TV replays show the Australian steaming into the first corner but is greeted by the Ferrari going slowly right in his way. The pair made slight contact but no major damage done.
Perez's Red Bull has sprung a leak which has caused his session to end early. Will that impact his qualifying with just two and a half hours to go before the start of Q1?
Plenty of lap time gains coming in, as Alonso goes fourth and Magnussen goes fifth. But nobody can live with Verstappen who puts in a 1m20.998s to go almost half a second faster.
Stroll, making up for effectively getting zero laps on Friday, has stuck to the harder compounds in this session which explains why he is rooted to the bottom of the times.
Hulkenberg's soft tyre run cannot match team-mate Magnussen but he still slots into seventh. The German locked up going into Turn 1 on his first push lap so it wasn't the cleanest of runs.
