Ferrari’s Charles Leclerc completed a practice hat-trick at the Spanish Grand Prix.
The championship leader edged out Red Bull’s Max Verstappen by just seven hundredths, with the Mercedes duo of George Russell and Lewis Hamilton third and fourth respectively.
Carlos Sainz finished fifth, one spot ahead of Sergio Perez at a sweltering Circuit de Catalunya, just north of Barcelona.
Leclerc, who holds a 19-point title advantage over Verstappen ahead of Sunday’s sixth round, has dominated all three practice sessions.
But the Ferrari driver will have Verstappen – winner of the past two races in Imola and Miami – hot on his heels for qualifying.
Both Mercedes cars could also be in the hunt, with Russell just 0.148secs back from Leclerc, and Hamilton a quarter-of-a-second adrift.
The Silver Arrows have brought a number of upgrades to Spain – including a revised floor and new front wing – and the early signs are encouraging for the team which has won the last eight constructors’ championships.
Russell is 23 points ahead of team-mate Hamilton after beating his seven-time world championship winning team-mate at four of the five grands prix.
And Hamilton (37) trailed the younger Briton (24) in the final one-hour running before qualifying.
“The sectors you gave me, is that to the fastest (driver) or to (George)?” asked Hamilton over the team radio.
“That’s to George, so that is best sectors to George,” answered his race engineer Peter Bonnington.
A tetchy Hamilton replied: “I only ever want to know the fastest.”
Mick Schumacher’s right-rear brakes caught on fire in the early moments with the German’s Haas team now facing a race against time to ensure his machine is ready to return to the track on Saturday afternoon.
Qualifying for Sunday’s race starts at 4pm local time (3pm Irish time).