It was probably the scariest moment of the season. Approaching Portier, the turn before the tunnel entrance, Jenson Button, making his one and only appearance of the 2017 season for McLaren, clumsily T-boned Sauber's Pascal Wehrlein.
Given the angle of the collison and the tightness of the corner, the young German's car flipped on its side and careered into the barriers protecting racing from the Med. It looked nasty and for a few moments it looked like Wehrlein was seriously hurt.
He struggled to set himself free from his car and any radio confirmation of his health was long-coming. Eventually, young Pascal signalled that he was okay and emerged from his car. As far as crashes go, it wasn't the most violent, but it served as a reminder of the dangers of the sport.