Bottas on pole at Imola with Hamilton alongside

By Alan Baldwin

(Reuters) - Valtteri Bottas powered to pole position for the Emilia Romagna Grand Prix at Imola on Saturday with the Finn's team mate and Formula One leader Lewis Hamilton locking out the front row for dominant Mercedes.

Red Bull's Max Verstappen qualified third, after a power unit scare in the second phase sent mechanics scrambling to fix his car, with AlphaTauri's Pierre Gasly a stunning fourth on the grid.

Mercedes need only a fourth place finish in Sunday's race to secure a record seventh successive constructors' world championship.

The pole, with a time of one minute 13.609 seconds, was a 13th in 13 races this season for the champions.

Sunday's race will be the first grand prix at Imola since 2006, with the track returning to flesh out a calendar ravaged by the COVID-19 pandemic, and the third in Italy this season.

"This track, when you push flat out, it's beautiful. I knew I had to improve in the last lap and I found those small gains that were needed," said Bottas, who was 0.097 quicker than Hamilton.

"It's a great feeling when you get those.

"It's going to be a good fight. It's one of the longest runs in the calendar into Turn One so no doubt Lewis and Max will be chasing me, but it's a good place to start and hopefully the pace is good."

Hamilton leads Bottas by 77 points, having won eight times so far this season, and is closing on a record-equalling seventh drivers' title although he will have to wait at least until Turkey in two weeks' time for a chance to clinch it.

"Valtteri did a great job. It was a pretty poor lap from myself. These things happen, you can't always get it perfect," said Hamilton, who had been quickest after the first flying laps in phase three.

(Reporting by Alan Baldwin in London, editing by Angus MacSwan and Pritha Sarkar)