Sergio Perez will head into qualifying for the Monaco Grand Prix having displaced Charles Leclerc at the top of the timing sheets in Free Practice 3.
The Mexcian traded laps with the home town hero throughout the latter stages of the session, but ended the hour move than 0.04 seconds faster than anybody else.
Carlos Sainz claimed third, over 0.3 seconds slower than his teammate, while Max Verstappen appeared to be lacking pace as he finished the session in fourth.
Result Free practice 3 - Monaco
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The fight to be best of the rest
McLaren's strong pace continued, with Lando Norris showing yet more signs that the team may be able to take the fight to Mercedes for qualifying. He ended the session in sixth.
Daniel Ricciardo was back out on track following his FP2 crash. The Woking-based squad were forced to change a number of his gearbox components overnight, but the Australian will not face a penalty due to the parts being within the allotted amount per season.
Mercedes waited 20 minutes to put their first push laps on the board. On the Soft tyre, they were more 0.9 seconds behind the pacesetters on just a two-mile circuit.
Lewis Hamilton was lapping faster than teammate George Russell, with both cars sporting the new front wing design debuted in Spain.
Mid-way through the session, Russell reported: "The ride is poor."
The bigger picture ahead of qualifying
AlphaTauri's strong pace remained during FP3, as Pierre Gasly ended the session in fifth. Valtteri Bottas (Alfa Romeo) and Kevin Magnussen (Haas) also placed inside the top 10.
Mick Schumacher (Haas), Fernando Alonso (Alpine), Esteban Ocon (Alpine), Yuki Tsunoda (AlphaTauri) and Daniel Ricciardo (McLaren) look to be the drivers who will be fighting to make it into Q3 during qualifying.
Williams and Aston Martin, meanwhile, will both be battling to make it out of Q1, having struggled with their pace all weekend.
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