After his spin, Colapinto has suffered fairly significant rear wing damage. It's not a quick job to change a rear wing, but he should get back out for a couple of laps at the end of the session.
Traffic is becoming a huge issue now, especially in the final sector. Russell comes close to slamming into the barriers at Rascasse as he attempted to avoid Albon's Williams.
An incident for Colapinto at the hairpin, as his car appears to push under braking, causing the Alpine to spin for no reason. That would be awkward if it happened in the race.
Hamilton reports that his seat is still loose. That's not great for the seven-time champion, especially as his pace from yesterday appears to have vanished.
A poor final sector for Antonelli means he fails to improve, but there's plenty of time yet.
Leclerc is on an out lap, but Antonelli is going faster still!
Leclerc responds by 0.019s, with his 1m13.355s displacing Antonelli at the top. Hamilton remains in fifth place. If this is a preview of qualifying, you'll need a decent sized bowl of popcorn!
As I'm typing this though, Antonelli returns serve with a 1m13.137s!
Championship leader Antonelli has entered the game. A 1m13.374s puts him 0.374s clear of Leclerc. Mercedes had no pace yesterday, but the team has certainly found something overnight.
The track is back to the optimum grip level, and these times are falling rapidly. Leclerc now bests Russell by 0.154s with a 1m13.748s. Will we see a 72-second time in this session?
A first effort from Verstappen puts him in third place, until Russell goes fastest! What a time to find some pace for Mercedes, with a 1m13.902s.
Stroll returns to the pits. He reports contact with the barriers, and he's in the garage for precautionary checks.
Lawson? What was you doing in second place? Highlighting how the times are falling, the Racing Bulls driver briefly goes to P2, but Norris knocks him down a place after going fastest with a 1m14.375s.
Norris narrowly avoided the wall with a snap of oversteer on the exit of the swimming pool. He goes third fastest, but here come the Red Bull and Mercedes pairs.
These times are tumbling big time, as Hamilton puts in a 1m14.390s. An error at the final corner saw him need a second stab at the brake pedal, so it wasn't his fastest final sector, but the rest of the lap was mighty.
Oh no! Perez now reports his front left brake is catching fire. He returns to the pits but this is now a major safety issue for Cadillac.
Mercedes and Red Bull are enjoying a leisurely start to the session, with all four drivers remaining in the pits for the moment.
Bottas is reporting smoke from his front right brake. It's the same brake that Perez suffered from in FP2. He suggests he won't use the brakes anymore, in order to prevent a repeat of his team-mate's fire.
A 1m15.246s from Hamilton, but Leclerc goes slightly quicker with a 1m15.184s. The times are notably slower than Friday, but as the track rubbers in, this will change.
As expected, soft tyres are the order of the day. It would be somewhat of a surprise if we saw anything other than soft rubber at all today.
We won't get to say this often, so let's enjoy it, but Bottas is setting purple sectors everywhere. Hamilton sets the first time, but Bottas bests it with a 1m21.115s.
Ok, they were prep laps, but a Cadillac is fastest!
But after 30-odd seconds, here comes Hamilton. Bottas, Leclerc, and Stroll follow the Ferrari pace-setter out.
Green light, and FP3 begins. No one rushes out.
Five minutes before the lights go green. This hour could make or break a weekend.
Secondly, McLaren breached the strict curfew rules last night in order to complete repair work on Lando Norris' car, which crawled to a halt in FP2. The repairs were described as "extensive" by the team, but all appears ready for the coming hour of action.
A couple of bits of news from overnight for you. First, we send our best wishes to Ferrari team principal Fred Vasseur, who will not be at the track today after being admitted to a local medical facility with an unspecified illness.
Get well soon Fred.

