Motor racing-Hamilton beats Rosberg to pole in Montreal

* Hamilton takes sixth pole in seven races

* Rosberg second on all-Mercedes (Xetra: 710000 - news) front row

* Vettel hit by power unit problem, Button absent (Adds detail, quotes)

By Alan Baldwin

MONTREAL, June 6 (Reuters) - Formula One world champion Lewis Hamilton seized pole position on Saturday for the Canadian Grand Prix with Nico Rosberg, his disappointed Mercedes team mate, beaten into second place on the starting grid.

The pole was championship leader Hamilton's sixth in seven races this season and a career 44th for the driver who races with the number 44 on his car.

"It wasn't the easiest of days," said Hamilton, who failed to get a quick lap under his belt in final practice, with some understatement. "I went into qualifying blind as to where the setup would be.

"It's definitely a positive to come back into this weekend on the right foot, to come back with the good pace I had from the last race after a difficult time," added the Briton.

Hamilton took the first win of his career in Montreal in his debut 2007 season with McLaren and has won at the Circuit Gilles Villeneuve three times in total.

A firm favourite for Sunday's race, he arrived here all the more determined after the blow of losing to Rosberg two weeks ago in Monaco thanks to a needless pitstop when he was leading comfortably.

Rosberg was on pole in Canada last season but could not find the speed when he needed it.

"What a rubbish end to qualifying," the German exclaimed as the chequered flag came down. "But here it's possible to overtake so it's not all over yet."

Hamilton, chasing his fourth win this season, leads Rosberg by 10 points after six races.

Ferrari's Kimi Raikkonen qualified third with fellow Finn Valtteri Bottas fourth for Mercedes-powered Williams.

Lotus pair Romain Grosjean and Pastor Maldonado filled the third row with Force India's Nico Hulkenberg in seventh.

Red Bull's Daniil Kvyat and Australian Daniel Ricciardo, last year's winner, were eighth and ninth respectively and Force India's Sergio Perez 10th.

Ferrari's Sebastian Vettel suffered power unit problems and failed to progress beyond the first session, qualifying 16th, while Felipe Massa lines up a place behind the German.

Max Verstappen will slip from 12th, however, due to a 15-place grid drop for two penalties, one for causing a crash in Monaco, the other for an unscheduled gearbox change.

The 17-year-old Dutchman will not be last though, with Britain's Jenson Button set to start from the pit lane after sitting out qualifying while McLaren worked on the Honda power unit.

Spanish team mate Fernando Alonso, yet to score this season, qualified 14th and moves up to 13th.

(Editing by Tony Jimenez)