A supporter holds up a sign supporting Liberal Leader Stéphane Dion as he speaks to supporters in Laval, Que. ((Adrian Wyld/Canadian Press))

A buoyant Stéphane Dion declared Thursday a "significant" milestone in the Liberal party's election campaign because for the first time, he and rival Stephen Harper agree on something.

The Liberal leader made the comment in reference to an earlier speech by Harper in which he repeatedly raised the possibility of "Prime Minister Dion."

"He said that the choice of this election next Tuesday is a choice between Prime Minister Harper and Prime Minister Dion. I agree," Dion said in a speech to supporters in Laval, Que.

He also celebrated another minor victory for the party — news that a Green candidate had the "courage" to pull out of the race to throw her support behind the Liberals in the Quebec riding.

Danielle Moreau told the Canadian Press she was withdrawing to rally behind the Liberal candidate Ryan Hillier in the Longueuil-Pierre-Boucher riding in an effort to help unseat Harper.

The Liberal leader sought to shore up support in vote-rich Quebec, where 75 seats are up for grabs.

He attacked Bloc Québécois Leader Gilles Duceppe's appeal to Quebec voters, asking them to vote Bloc to keep the Conservatives from securing a majority. The Liberal leader called that misguided reasoning.

"We have more to do than to block [Harper]," Dion said in French. "We have to replace him!"

"With Harper we're going backwards. With Duceppe we're blocking. With Dion we're going forward," he said.

At Parliament's dissolution on Sept. 7, the Liberals and Conservatives each held 11 seats in Quebec, while the Bloc held 48. The NDP had one seat, Independents had two and two ridings were vacant.