Defending World Drivers champion Dexter Dunn settled off the pace in seventh after the first round of the 2017 series in Canada on Sunday.

The New Zealand star finished a bold second in the opening heat at Century Downs Racetrack, Calgary, but couldn't advance among the place-getters in the other four first-round heats.

He did win the final event on the card, but it wasn't a world championship race.

Fellow New Zealand representative Mark Purdon had a luckless first day. He is 10th position among the 11 drivers.

United States driver Marcus Miller, who tasted success in two of the first-round heats, leads with 57 points from Canada's James MacDonald, who also won two WDC races.

MacDonald was victorious in the second and fifth races, first clearing to command from post eight after the first quarter and holding off the competition for the victory in 2:03.1 aboard Lucky Lucka ($19.70) and then sending Barossa Blue Genes ($6.70) three-wide off cover approaching the third quarter mark and drawing clear in the stretch to win by two and a half lengths in 2:03.3.

''It's a whole different ball game and I've never been involved in anything like this," said MacDonald of the international tournament. ''I'm really excited to be doing it and thankfully having a little bit of success.''

The drivers will head to MacDonald's home track at Mohawk Racetrack in Campbellville, Ontario, for the second WDC leg on Tuesday (NZ time).

First-round points: Marcus Miller (USA) 57, James MacDonald (Canada) 50, Shane Graham (Aust) 48, Bjorn Goop (Sweden) 43, Gehard Mayr (Austria) 38, Mika Forss (Finland) 34, Dexter Dunn (NZ) 29, Rik Depuydt (Belgium) 25, Noel Baldacchino (Malta) 24, Mark Purdon (NZ) 21, Erik Hoitamt (Norway) 16.