Co-operation was a big topic during the first federal Liberal leadership debate.

The nine candidates joined each other on stage in Vancouver Sunday.

The only real sparks flew during the topic of electoral co-operation, on whether the party could win an election on its own.

MP Joyce Murray says he would join forces with the NDP and the Greens to defeat the Tories. But the other candidates rejected the idea.

"I am completely closed to any co-operation with the NDP," said MP Justin Trudeau.

There were also a couple of jabs at Trudeau over his inexperience in politics.

There will be four more debates in Toronto, Montreal, Winnipeg and Halifax.

(With files from The Canadian Press)