Drivers, including Leclerc, said they would query the decision to delay the deployment of the safety car following Verstappen's crash late in the race.
Verstappen crashed with five laps to go and the race at his mercy.
It was the Briton who started from pole, with Vettel down in fourth, but the pair occupied the two leading positions in the race following the deployment of the Safety Car in the early stages.
It is then switched off for the start but Hamilton confirmed he had nudged it on again by accident.
Q3 was halted with a minute remaining when Gasly's teammate, Japanese rookie Yuki Tsunoda, crashed at turn three, with Carlos Sainz in the following Ferrari taking quick avoding action, locking his wheels and smashing into a safety barrier Leclerc was on course to confirm Ferrari's return to form after their woeful 2020 when he qualified fastest in Monaco but crashed at the end of Q1 in his home race.
The top five order settled for the next eight laps, with Hamilton unable to keep up with Pérez through the corners, whilst closing the gap again down the straights.