Daniel Ricciardo edged out team mate Max Verstappen to put Red Bull ahead of the field in the opening practice session for this weekend's Monaco Grand Prix.
The senior bulls achieved their fastest on the pink hypersoft tyre, as did fellow front-running followers Lewis Hamilton, Sebastian Vettel and Kimi Raikkonen.
Monaco Grand Prix - Free Practice 1
|1||Daniel Ricciardo||Red Bull||1:12.126s||36|
|2||Max Verstappen||Red Bull||1:12.280s||+ 0.154s||25|
|3||Lewis Hamilton||Mercedes||1:12.480s||+ 0.354s||34|
|4||Sebastian Vettel||Ferrari||1:13.041s||+ 0.915s||40|
|5||Kimi Räikkönen||Ferrari||1:13.066s||+ 0.940s||38|
|6||Carlos Sainz||Renault||1:13.456s||+ 1.330s||40|
|7||Valtteri Bottas||Mercedes||1:13.502s||+ 1.376s||39|
|8||Sergio Pérez||Force India||1:13.717s||+ 1.591s||39|
|9||Romain Grosjean||Haas||1:13.943s||+ 1.817s||24|
|10||Sergey Sirotkin||Williams||1:13.962s||+ 1.836s||40|
|11||Esteban Ocon||Force India||1:14.000s||+ 1.874s||39|
|12||Brendon Hartley||Toro Rosso||1:14.034s||+ 1.908s||46|
|13||Nico Hülkenberg||Renault||1:14.134s||+ 2.008s||38|
|14||Pierre Gasly||Toro Rosso||1:14.240s||+ 2.114s||38|
|15||Stoffel Vandoorne||McLaren||1:14.291s||+ 2.165s||37|
|16||Charles Leclerc||Sauber||1:14.521s||+ 2.395s||39|
|17||Fernando Alonso||McLaren||1:14.637s||+ 2.511s||16|
|18||Lance Stroll||Williams||1:14.782s||+ 2.656s||43|
|19||Marcus Ericsson||Sauber||1:15.206s||+ 3.080s||39|
|20||Kevin Magnussen||Haas||1:18.801s||+ 6.675s||7|
The bulk of the field kicked off FP1 and their installation laps on Pirelli's hypersoft tyre, a compound that will be omnipresent this weekend.
Hamilton and Bottas swapped positions at the top the timesheet in the early part of the session, but an up-to-speed Daniel Ricciardo soon overhauled both Silver Arrows.
The weekend's first yellow flag was brandished after just 15 minutes, courtesy of Williams' Sergey Sirotkin strangely hitting the pitwall on the inside as he came out of the final corner.
Verstappen took over from his team mate at the top but the Aussie recouped the lead while Vettel moved himself and Ferrari into the top three around 30 minutes in to the session.
Red Bull's duo continued to lay down the markers however with Maximum Max deposing once again the Honey Badger, with both bulls running on the hypersoft rubber.
Meanwhile, down at McLaren, Fernando Alonso was complaining of a long brake pedal. The team's initial diagnosis found nothing wrong but given the persistence of the issue, the crew decided to take the floor off the Spaniard's MCL33 to investigate more thoroughly.
Halfway through the session, Lewis Hamilton upped the pace, achieving a benchmark time of 1m12.480s that put him at the top of the leaderboard and 0.243s clear of Verstappen.
The 20-year-old fought back immediately however, edging out the Mercedes by 0.114s before heading down the Ste Devote escape road after a massive lock-up.
The Red Bull driver's reverse move back on to the track was frowned upon however by the stewards who decided to investigate the driver for "failing to rejoin the track in a safe manner".
Back at the tail end of the field, Alonso was joined by both Haas drivers in the "minimum number of laps accomplished" department, with McLaren and the US outfit dealing with their respective issues.
With twenty minutes to go in the first practice session, Ricciardo again deposed his team mate with a 1m12.126s lap that put him 0154s clear of Verstappen.
Positions remained unchanged at the front, the Milton Keynes-based outfit and its two bulls confirming at the outset their status as favourites for the Monaco Grand Prix.