Louis Hamilton was fastest in both Friday practices at the Baku street circuit. (Source: Reuters)

Triple world champion Lewis Hamilton completed his domination of practice for Azerbaijan’s first Formula One grand prix with the fastest time in Saturday’s final session before qualifying.

The Mercedes driver, who was fastest in both Friday practices at the Baku street circuit, lapped with a best time of one minute 44.352 seconds late in the session — slower than his best the previous day.

Team mate and championship leader Nico Rosberg was second, 0.258 slower.

Force India’s Nico Hulkenberg, who won the Le Mans 24 Hours sportscar race this time last year but is unable to defend the title due to the calendar clash, was best of the rest on the timesheets.

Hamilton was 1.188 seconds clear of Hulkenberg.

The session was halted shortly before the scheduled finish when Hulkenberg’s Mexican team mate Sergio Perez hit the wall at Turn 15, the same spot where Red Bull’s Daniel Ricciardo crashed on Friday.

Ricciardo was fourth on Saturday, ahead of Ferrari’s Sebastian Vettel, Perez and the Australian’s 18-year-old Dutch team mate Max Verstappen.

Team workers modified the track overnight, removing kerbs that had lifted in Friday practice and moving the white lines at the pit lane entry.

However, there was still a worrying moment when a loose drain cover flipped up in the pitlane after Valtteri Bottas’s Williams passed over it.

The car was damaged and returned to the garage while marshals placed a traffic cone in front of the hole.

Some drivers, notably Rosberg and McLaren’s Jenson Button, had complained about the lack of runoff areas and pitlane entry but they got short shrift from commercial supremo Bernie Ecclestone.

“If they don’t want to drive, they don’t have to,” said the 85-year-old.

“It’s up to them. This is the circuit. If they don’t like it, go home.

“One of them, I think Nico, was complaining about the speed into the pitlane. So I said to the people ‘go and have a look and see if he’s got a brake on the car’. It’s up to him how quick he is.”