Red Bull triumphed 1-2 at the Azerbaijan Grand Prix, giving Max Verstappen a 21-point lead over teammate Sergio Pérez in the Formula One world championship on a dismal day for Ferrari.
Verstappen had a rocky start to the defence of a title he won in such dramatic way the year before
Leclerc, who has started from pole position in six of the season's eight races, led the race until an engine breakdown after 19 of the 51 laps.
Carlos Sainz, Leclerc's teammate, also retired early due to hydraulic issues
Pérez, a Baku specialist who won in Monaco a fortnight ago, led the early laps after beating Leclerc into the first corner,
But after outqualifying Verstappen for the second consecutive race, he suffered worse tyre degradation and had to hand over the lead to the defending champion after 14 laps.
His 25th victory tied him with Jim Clark and Niki Lauda, two former racing giants.