The first stumble in the NDP's unprecedented climb to power in Alberta was registered Thursday night with a byelection victory by the Opposition Wildrose in a Calgary constituency that had been held by the Conservatives since 1971.

WildroWith 57 of 66 polls reporting -- and only the advance polls unaccounted for -- Wildrose candidate Prasad Panda led with 35 per cent of the vote compared to 27 per cent for NDP candidate Bob Hawkesworth, a former MLA and Calgary city councillor.

Tory candidate Blair Houston, a restaurant owner, was a close third with 24 per cent of the vote.

Less than 90 minutes after polls closed, the NDP had issued a concession through a news release from Finance Minister Joe Ceci congratulating Panda on the victory.

"We knew that it would be an uphill battle given the history of the riding and the economic challenges we face because of the collapse in oil prices," said Ceci.

"We hear the concerns about oil prices loud and clear. And we are working hard to release an economic recovery plan in the coming weeks."

The byelection in Calgary-Foothills was called after former Tory premier Jim Prentice won the riding on election night in March only to resign from politics the same night when his party was handed their walking papers by Premier Rachel Notley's NDP.

Some pollsters, including Janet Brown of Calgary, expected it to be a hotly contested race between the NDP and the Wildrose.

She suggested the NDP was eager to win to prove their general election victory wasn't a fluke, while the Wildrose needed to prove it could win an urban riding.

Notley rejected the premise, saying the outcome of the byelection was not a "litmus test" for her government, which has a comfortable 53-seat majority in the 87-seat legislature.

Nevertheless, she paid multiple visits to the constituency during the month-long campaign.

The race was nasty at times.

The Wildrose, which doesn't hold a seat in Edmonton or Calgary, accused the NDP of trying to scare voters by suggesting the Wildrose backs sweeping and punishing civil service job cuts.

The NDP fired back at the Wildrose for a campaign pamphlet, written in Cantonese, that compared the government to communists. The Wildrose said it meant to say socialists and that was lost in translation.

Panda said prior to Thursday's vote that people he was talking to weren't convinced the New Democrats could lead Alberta back to prosperity.

"They're realizing the NDP tend to believe they have a mandate to implement their ideological agenda, whereas people are really worried about jobs and the economy," he said.

Houston said despite Prentice's abrupt departure on election night before all the votes were even counted, he did not encounter residual anger at the party, adding he himself was upset when Prentice stepped down.

It was the third time in a little over 10 months that Calgary-Foothills voters had gone to the ballot box.

In preparation for taking over the Alberta Conservatives after the resignation of former premier Alison Redford, Prentice had won the constituency in a byelection in October 2014.