FP3: Verstappen remains ahead but Mercedes and Ferrari close in

Max Verstappen picked up where he left off on Friday by topping the final practice session for the Mexican GP, the Red Bull driver clocking in with a 1m16.284 to edge the revitalized duo of Lewis Hamilton and Sebastian Vettel.

While Mercedes significantly improved its pace from yesterday, Valtteri Bottas was sidelined in the session following a suspected hydraulic failure which will necessitate an engine but no grid penalty.

Renault's Carlos Sainz and Nico Hulkenberg appeared to lose a bit of momentum overnight, while Sauber's Charles Leclerc broke into the top-six, ending the session just 0.775s adrift from Verstappen.

2018 Mexican Grand Prix - Free Practice 3

Both Mercedes and Ferrari had their work cut out for them at the outset of FP3 given their deficit to Red Bull after yesterday's running, and their ambition to challenge for pole this afternoon.

Tyres, and more specifically Pirelli's hypersoft compound, have been the crux of the matter for the front-runners - and for most of the teams, but Mexico City's high altitude and the specific demands it imposes on engines is also a big part of the performance equation.

The Silver Arrows squad admitted on Friday that it had been forced to turn down the power of its engines to keep its unit's cooling in check.

With just 15 degrees Celsius in the air - and a still damp track made greener by some morning rain - the session kicked off under much cooler conditions, perhaps allowing Mercedes to dial in a bit more power as it set out to hone its set-up ahead of this afternoon's all-important qualifying session.

• Pirelli's Isola: 'Hypersoft degradation will impact qualifying strategies'

Pierre Gasly, Marcus Ericsson and Stoffel Vandoorne were the first to venture out for a cautious installation lap when the lights went green, with all cars fitted with Pirelli's intermediate rubber as the track continued to dry, although the threat of thunderstorms in the area were looming.

Hamilton and Bottas also completed exploratory laps but for the most part the field remained confined to their garage, waiting for the gloomy skies to clear up somewhat while also avoiding to burn unnecessarily through sets of inters that may be required later on in the day.

Thirsty minutes in to the session, the action finally kicked off in earnest, and - low and behold - a McLaren put itself at the top of the timesheet, courtesy of Fernando Alonso, a feat so rare these days that the Spaniard was told by his pitwall "I know you don't hear this very often... so we are P1, purple in every sector!"

The joy was predictably short-lived however as Kimi Raikkonen quickly overhauled Alonso by 0.4s, just before Charles Leclerc jumped to the front, clocking in with a 1m18.952s.

Unfortunately, Kevin Magnussen was nowhere to be seen, his Haas crew proceeding with a costly inter-cooler change on his car that would prevent the Dane from running.

Bottas and then Vettel upped the pace with 20 minutes to go, the German laying down a lap in 1m17.836. Immediately after however, the VSC was activated when the Finn was seen stranded on the side of the track, reporting back on the radio that he suspected a hydraulic failure, an alarming incident just a couple of hours from qualifying.

Up front, Verstappen and Sainz had moved up the order to secure P2 and P3, the Red Bull driver positioning himself just 0.082s behind Vettel.

But once again, the order was shaken up on the back of efforts from Leclerc and Hamilton, the Sauber driver putting himself in command with an impressive 1m17.059s, over 0.7s faster than Vettel!

A succession of flying laps on hypersoft tyres ensued in the closing minutes of the session, Verstappen completing his third clean sweep of the weekend with a 1m16.385, edging a revived Hamilton by 0.153s and Vettel by 0.259s.

So it looks like F1's mighty trio of front-runners is reunited once again, which promises a thrilling 60-minute shootout this afternoon.

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