After Mercedes followed up its five consecutive one-two finishes with first and second place in 'Friday' practice for the Monaco Grand Prix, you might think this guarantees more of the same weekend. But there was at least the hint of a possible threat - and it wasn't from Ferrari.
Max Verstappen split the two Mercedes drivers in the morning practice session, but was unable to complete a performance run in the afternoon thanks to a radiator leak caused by debris flying into the airbox. At this point, Verstappen was still on his first set of softs. When he hit the track for seven laps late on he didn't make a proper qualifying simulation attempt.
Even Verstappen in a Red Bull that is a little slower could be within striking distance
Verstappen would surely have lapped quicker than Pierre Gasly - he had been 0.984 seconds faster than his team-mate in the morning. Were that gap repeated in practice two that would have put Verstappen fastest, as Gasly was 0.820s slower than pacesetter Lewis Hamilton.