Lewis Hamilton believes Mercedes are playing catch-up at the Russian GP due to Ferrari and Red Bull's "big progressions" - while Toto Wolff admits the Silver Arrows are "struggling to find the clues" to unlock their pace.
Mercedes, looking to avoid their first four-race drought since 2013 this weekend, are already on the back foot in Sochi following the first day of practice, with Charles Leclerc and Max Verstappen sharing the spoils in P1 and P2.
