SYDNEY, N.S. -- Canada's Rachel Homan defeated Italy's Stefania Constantini 8-7 in an extra end to remain unbeaten at the world women's curling championship.

Homan's Ottawa-based team (5-0) forced the Italians (4-1) to a single in the 10th end and secured the win when Constantini's final throw overcurled to leave the Canadian rock as shot stone.

Homan and teammates Tracy Fleury, Emma Miskew and Sarah Wilkes will return to Centre 200 in the evening to play defending champion Silvana Tirinzoni of Switzerland (5-0).

Homan, who ran the table at the Canadian championship last month, has won 21 straight games and is 54-5 on the season.

Tirinzoni, who has secured four straight world titles, took a 41-game winning streak at this event into her afternoon matchup against Norway's Marianne Roervik.

Competition continues through Sunday.