Lewis Hamilton believes he is involved in the "ultimate challenge" after moving to the top of the Formula One drivers' championship standings for the first time in 18 months.

Hamilton clinched a stunning Canadian Grand Prix victory in a pulsating 70-lap showdown that ebbed and flowed just as much as the title race continues to do at present.

"The race was one of the toughest so far, but that's what you want, and it was another one-two for us, so I'm very happy and proud of the team. They've done a great job," said Hamilton. "It was a tremendous challenge, probably the ultimate challenge for me throughout the year so far."

It was Hamilton's 13th career victory and, allied with his win in Turkey two weeks ago, represents his first back-to-back success in almost two years.

Not since the end of his title-winning season in 2008 has Hamilton led the championship, but the McLaren star holds a three-point lead over team-mate Jenson Button after the team's third one-two of the year.

After eight races, Hamilton is now the sixth different leader of the championship, and with 11 grands prix remaining, the nip and tuck nature is sure to continue.

"You can see how tight this championship is, and I don't know if it's dependant on the new points-scoring system, but this year is so close," added Hamilton.

"All the best drivers are in the top teams, and they're all very, very competitive.

"It's the ultimate challenge I think I've experienced in Formula One, perhaps in Formula One history maybe.

"There are so many of us up there pushing right to the wire, which I'm sure means the championship will remain close. There will be lots of ups and downs during the rest of the season, but let's hope we are able to stay in the front line."