Lewis Hamilton was back on form after his blip in the previous race in Russia and took the fastest times in both the Friday (12 May) practice sessions at the Circuit de Catalunya in Barcelona. He was marginally ahead of teammate Valtteri Bottas.
Mercedes have brought the most noticeable upgrade package to the fifth race of the season and it seemed to have a considerable amount of advantage over the rest of the grid. They have answered their shortcomings against Ferrari in recent races and were comfortable quicker than their nearest rivals.
Kimi Raikkonen was the fastest Ferrari and just over a tenth faster than his teammate Sebastian Vettel. The latter had a horrendous day in the car and admitted after FP2 that there was a big chunk of speed still to be found.
The final practice on Saturday and the qualifying session will provide a true indication of how far Mercedes have forged ahead or if Ferrari are still within fighting distance to fight for the win in Barcelona.
Red Bull Racing had most of the attention of the grid on Friday owing to expectations of a major upgrade package to reduce their deficit to the top two teams. They certainly did close the gap but remained the third best team after two sessions.
The Renault team have also made a jump up in the midfield pecking order after Nico Hulkenberg and Jolyon Palmer clocked the seventh and eighth best times of the day.
Where to watch live
The third free practice session begins on 14 May at 10am BST, while the qualifying session starts at 1pm BST. Sky Sports F1 and Sky Sports F1 HD will provide live coverage of both events in the UK.
Real-time internet updates are available on the Live Timing section of the sport's official website.
Top 10 results of the second practice session from the Circuit De Catalunya, Barcelona