Max Verstappen was leading Red Bull one-two in final practice before the Monaco Grand Prix as Lewis Hamilton’s accident ended the session under the red flags.
The Mercedes driver found the fence at Mirabeau in the closing moments of the hour-long tour, shortly after Kevin Magnussen stopped at the track.
Verstappen and Sergio Perez traded places at the top of the timetable for most of the session, while Lance Stroll in third suggested Aston Martin had pace to burn ahead of qualifying.
Stroll was the first man to drive out of the pits as Free Practice 3 began, completing an installation lap before immediately returning to the Aston Martin garage.
It was a race pit stop, the team was replacing his medium rubber with a set of new hard tires.
They did the same for Fernando Alonso, while the Scuderia AlphaTauri duo of Yuki Tsunoda and Nyck de Vries were the only other drivers on the track.
Like Friday, conditions remained hot and sunny, a far cry from long-term forecasts that predicted rain.
Perez was the first Red Bull rider on the track, a Mexican using a set of soft tyres.
Finishing a fast lap, Esteban Ocon stopped in the tunnel.
The Frenchman was able to get going again, Perez flying past Alpine en route to 1:15.641s after eight minutes.
Pierre Gasly in the sister Alpine was second fastest thanks to being the only driver other than Perez to complete a lap.
His best time was 1:15.990, also on the soft tyres, 0.6 seconds behind Perez.
The circuit got busier after 15 minutes of running with more care.
This moved Carlos Sainz up to second, just 0.066s slower than Perez, while Stroll was just 0.01s further down in third.
Traffic was an issue around the short circuit, although Lando Norris found some clear air when he made it 1:14.905.
He didn’t stay on top of the session for long as both Stroll and Perez improved the time of the McLaren driver.
After 20 minutes, Verstappen recorded his first timed lap of 1:13.794, giving him a 0.5 second advantage over his teammate.
Yuki Tsunoda turned a strong lap and finished third when Charles Leclerc asked the Ferrari pit wall if he had brushed against the pool rail.
His engineers have given him all clear, as replays suggest the slightest abrasions with the fence barrier that teammate Sainz hit in Free Practice 2.
It turned out to be a busy session, with times steadily dropping; with 35 minutes to go, Perez was fastest than Alonso while Verstappen dropped to third.
This suggested that the track was getting better and the drivers were getting more comfortable and confident behind the wheel.
An intriguing battle for first place then developed, with Perez and Verstappen trading places for some time, with the Dutchman eventually leading the group with a time of 1:12.898.
In the Ferrari, Leclerc was unhappy with the handling of his car in the swimming pool section, complaining about the bottom on the approach to the complex.
The Monegasque driver was fourth fastest at the time, just over 0.6 seconds short of Perez’s session best time (his battle with Verstappen continued).
The battle between the Red Bull drivers at the top of the times table was not settled as Verstappen recorded 1:12.776s – though times were still dropping at the one-lap pace shown in Friday’s second free practice.
There was little between the Red Bull pair who had a lead of over 0.5 seconds over Sainz in third place.
Mercedes showed well, with Hamilton in fifth and Gasly in sixth, while Alonso was almost a full second off the pace in seventh.
Aston Martin clearly had more pace as with 18 minutes to go, Stroll passed Sainz in third with a lap of 0.166 seconds off.
Kevin Magnussen’s error with just over 10 minutes left sent the Haas driver to the emergency exit at Sainte Devote.
Although he was able to recover, he soon reported a lack of power steering and was immediately told to stop the car.
He did so by approaching the Porter, out of danger, next to a gap in the fence that could easily be driven through by a car.
A virtual safety car was deployed to cover the Dane as he exited the car and the stewards removed him.
It was completed in typical Monaco fashion and within two minutes the track was green again.
Shortly after the track turned green, Hamilton pitted on Mirabeau to draw the red flag.
The Mercedes driver lost the rear of the car as he turned the right-hand exit, correcting the skid, but ended up in the barrier.
This left Hamilton with damage to his left front wheel, and his engineer advised him not to try to recover the car.
With little time left and the Mercedes proving harder to recover than Magnussen’s Haas, the session did not resume.
He was the quickest to leave Verstappen since Perez, with Stroll third ahead of Sainz, Norris, Gasly and Leclerc.
Piastri was 19th fastest, 1.2 seconds behind Verstappen but only 0.6 seconds behind his teammate.
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