A new mayoral election poll commissioned by CTV Calgary and The Calgary Herald is being described as a "game-changer."

The poll by Leger Marketing finds that, in a surprising development, the two person race to become Calgary's mayor has now turned into a three person race.

Among decided voters, former alderman Ric McIver still has the lead at 33.3 per cent.

But Mount Royal University professor Naheed Nenshi has closed his sizable gap and is now not only now firmly in the race, but has leapfrogged into second place with 30.1 per cent support among decided voters, according to the poll.

Former news anchor Barb Higgins is close behind in third place with 29.6 per cent of the vote.

The results put all three candidates in a statistical tie when the margin of error of 4.4 per cent is taken into account.

University of Calgary political scientist Lisa Young says Nenshi's campaign has been gaining strength and he will now have more ammunition at his disposal to convince voters he is a viable alternative to those voting specifically against McIver.

Young says McIver, Nenshi, and Higgins all need to focus on getting their supporters out on election day and the push will be on for all three to get their message out.

The rest of the candidates in the race are barely registering with decided voters. Bob Hawkesworth, who is now out of the race, led the rest of the pack with just 1.9 per cent. Wayne Stewart has just 1.8 per cent support, Joe Connelly has 1.7 per cent, Craig Burrows has 1.2 per cent, and Barry Erskine has less than one per cent.

Undecided voters still make up a significant block in the new poll at 36.9 per cent.

Young says the front-runners will now be working overtime to try and win those people over to their side.

Leger Marketing conducted the telephone survey with 500 randomly selected Calgary adults (aged 18+) from October 6-11, 2010. The margin of error for the survey is +/-4.4%, 19 times out of 20.

Watch the CTV News at 6 for more poll results, including which candidate voters said they did not want to become Calgary's next mayor.

And for more coverage of the Leger Marketing poll, visit The Calgary Herald by clicking here.