The front three drivers of Hamilton, Max Verstappen and Sebastian Vettel were covered by just 0.166 seconds, ahead of Pierre Gasly who finished the session in fourth.
With Bottas running into trouble and Charles Leclerc struggling to impress in sixth, it gave Kevin Magnussen a chance to give the Haas team something to cheer about, putting his car in a solid fifth position.
New weekend, new parts
Some of the teams have been able to bring new parts to help with the high-downforce circuit.
Ferrari have brought a new style of 'boomerang wings' for the bargeboard, on top of being able to update some of the parts on the aerodynamics package.
Racing Point have added some new parts to the car, with one of the biggest changes being updates to the suspension package in the hope of closing the gap to best-of-the-rest McLaren.
Not even two laps into practice and speculation of rain was being thrown around the paddock. Most drivers started on the softer compound tires, with a few teams changing to intermediates later on in the session.
There were even reports of lightning, with stormy conditions threatening the session throughout.
Following on from his poor showing in the German Grand Prix last time out, it doesn't seem as if things are getting any easier this weekend for Finnish driver Bottas.
After one lap he was forced to pull into the pits with engine trouble and just moments later he was out of the car and the power unit was being swapped over in the garage.
Sainz also had a substantial issue with his car, complaining of water pressure issues. With around ten-minutes to go in the session, his McLaren was also in pieces in the garage.
Some of the kerbs on the track had caused some drivers issues with their front wings. Turn four was a particular hotbed for problems, however it seemed that many of the drivers were struggling across the track on the raised kerbs.
Racing Point's Lance Stroll and Sergio Perez were struggling through the tricky left-right complex towards the back of the lap. Whereas both Haas and Red Bull seemed to pick up some damage at some point during the lap due to the kerbs.
First Practice results:
- Lewis Hamilton - 1.17.233
- Max Verstappen +0.165s
- Sebastian Vettel +0.166s
- Pierre Gasly +0.449s
- Kevin Magnussen +0.709s
- Charles Leclerc +0.955s
- Nico Hulkenberg +1.184s
- Lando Norris +1.298s
- Carlos Sainz +1.469s
- Kimi Raikkonen +1.554s
- Daniel Ricciardo +1.661s
- Romain Grosjean +1.740s
- Daniil Kvyat +1.749s
- Alexander Albon +1.990s
- Sergio Perez +2.092s
- Antonio Giovinazzi +2.255s
- George Russell +2.416s
- Lance Stroll +2.489s
- Robert Kubica +3.089s
- Valtteri Bottas - No Time