Max Verstappen headed a Red Bull one-two in final practice for the Monaco Grand Prix as a Lewis Hamilton crash saw the session end under red flags.
The Mercedes driver found the fence at Mirabeau in the closing moments of the hour-long outing, shortly after Kevin Magnussen had stopped on track.
Verstappen andSergio Perez swapped places at the top of the timesheets almost throughout the session, while Lance Stroll in third suggested Aston Martin has pace to burn heading into qualifying.
Stroll was the first man out of the pits as Free Practice 3 began, completing an installation lap as he immediately returned to the Aston Martin garage.
It was for a racing stop, the team swapping his medium rubber for a set of new hards.
They did the same for Fernando Alonso too, while the Scuderia AlphaTauri duo of Yuki Tsunoda and Nyck de Vries were the only other drivers on track.
As it had been on Friday, conditions remained hot and sunny, a far cry from the long-range forecasts which predicted rain.
Perez was the first Red Bull runner on track, the Mexican using a set of soft tyres.
As he completed his fast lap, Esteban Ocon stopped in the tunnel.
The Frenchman was able to get going once more, Perez flying by the Alpine en route to a 1:15.641s after eight minutes.
Pierre Gasly in the sister Alpine was second fastest, courtesy of being the only driver other than Perez to have completed a lap.
His best was a 1:15.990s, also set on the soft tyres, 0.6s away from Perez.
The circuit became busier after 15 minutes of running with more care venturing out.
That saw Carlos Sainz rise to second fastest, just 0.066s slower than Perez, while Stroll was just 0.01s further back in third.
Traffic was a problem around the short circuit, though Lando Norris found some clear air as he banked a 1:14.905s.
It didn’t stand as the session’s best for long as both Stroll and Perez bettered the McLaren driver’s time.
With 20 minutes elapsed, Verstappen recorded his first timed lap – a 1:13.794s leaving him 0.5s clear of his team-mate.
Yuki Tsunoda banked a strong lap to sit third as Charles Leclerc asked the Ferrari pit wall if he’d brushed the barrier at the Swimming Pool.
He was given the all clear by his engineers as replays suggest the faintest of rubs with the barrier on the fence team-mate Sainz clouted in Free Practice 2.
It proved to be a busy session with times dropping constantly; with 35 minutes to run Perez was fastest from Alonso, while Verstappen had slipped to third.
It suggested an ever-improving track, and drivers becoming both more comfortable and confident behind the wheel.
An intriguing battle then developed for top spot, with Perez and Verstappen swapping it for a time, the Dutchman ultimately heading the pack on a 1:12.898s.
At Ferrari, Leclerc was unhappy with the handling of his car around the Swimming Pool section, complaining of bottoming on approach to the complex.
The Monegasque driver sat fourth fastest at the time, just over 0.6s down on Perez’s best of the session (his battle with Verstappen continued).
The battle between the Red Bull drivers at the top of the timesheets wasn’t done as Verstappen logged a 1:12.776s – though times were still down on the single lap pace shown in Free Practice 2 on Friday.
There was little between the Red Bull pairing, who were both more than 0.5s clear of Sainz in third.
Mercedes showed well, with Hamilton in fifth and Gasly sixth, while Alonso was almost a full second away from the pace in seventh.
Aston Martin clearly had more pace, as with 18 minutes remaining Stroll usurped Sainz for third fastest with a lap 0.166s away from the spot.
A mistake from Kevin Magnussen with a little over 10 minutes remaining saw the Haas driver head up the escape road at Sainte Devote.
Though able to recover he soon reported a lack of power steering, and was promptly told to stop the car.
He did so on approach to Portier, out of harm’s way, adjacent to a gap in the fence where the car could be easily wheeled.
The Virtual Safety Car was deployed to cover the Dane climbing free from the car and marshals clearing it away.
It was completed in typically efficient Monaco fashion, and within two minutes the circuit was green once more.
Soon after the track went green, Hamilton slid off at Mirabeau to draw the red flag.
The Mercedes driver had lost the rear of the car as he turned into the downhill right-hander, correcting the slide but ended up in the barrier.
It left Hamilton with front-left damage, his engineer advising him to not attempt to recover the car.
With little time remaining, and the Mercedes proving more difficult to recover than Magnussen’s Haas, the session was not resumed.
It left Verstappen fastest from Perez, with Stroll third ahead of Sainz, Norris, Gasly, and Leclerc.
Piastri was 19th fastest, 1.2s away from Verstappen’s time but only 0.6s away from that of his team-mate.