Max Verstappen showed promising pace in the first Free Practice session for this weekend's Azerbaijan Grand Prix at the Baku City Circuit, setting the fastest time, with Daniel Ricciardo completing a superb early afternoon for Red Bull in second.
Hamilton also set his best time on the soft tyre and was just over half a second slower than Vettel. The lack of grip between the softest compound available this weekend and the smooth Baku surface was clear to see, but Hamilton will be left thumbing through the book of racing driver excuses after being outpaced by Lance Stroll, Sergio Perez, Daniil Kvyat and Esteban Ocon.
Vettel had another off, this time at Turn 8, where he was joined by Massa.
With 20 minutes left, the red flag halted the session after Perez mangled both wheels on the right side of his auto snaking through into a tight Turn 8. With just minutes of the session remaining, the 19-year-old lost control of his auto under braking and span into the nearside barrier.
Lewis Hamilton endured a slightly frustrating morning of action in his Mercedes as he finished fifth-fastest after failing to produce a quick and clean lap in the latter stages of the action. The duo did most of their running in the final few minutes.
Haas driver Romain Grosjean endured a particularly troubled time.
Ferrari, the Silver Arrows' main rivals at the top of the constructors' standings, fared little better with Vettel and Raikkonen both leaving the track on more than one occasion.
Red Bull has brought a aero updates to Baku while Renault has made improvements to the engine.
Eighteen of 22 cars finished the challenging anti-clockwise track a year ago, despite driver complaints about safety, although there were signs during practice that the narrow, winding circuit will cause some trouble during Sunday's race.
"I've had that before you know so your heart rate doesn't go up".
The teams settled in to longer runs on the supersoft tyres for the remainder of the session, and once again Max Verstappen looked handy, lapping quicker than both Mercedes cars, sometimes by more than a second.
Daniel Ricciardo finished the morning session second on the timesheets, nearly half a second down on his team-mate, while championship leader Sebastian Vettel was third in his Ferrari. He appeared to overshoot the corner, then realised a bit too late he needed to take the escape road and ended up sliding his vehicle into the barriers.