Canada swept hosts Spain 3-0 in the Billie Jean King Cup finals on Wednesday, to get off to a strong start in Group C.

Earlier, Italy scored an impressive 2-1 win over France in their opening Group D tie, winning both singles rubbers.

Canadian rookie Marina Stakusic, 18, beat Rebeka Masarova 6-3, 6-1 in a brilliant display, before Leylah Fernandez edged Sara Sorribes 7-6 (10/8), 7-6 (9/7) to clinch the tie.

Stakusic, ranked 258th in the world, made light work of Masarova, who is 65th for her first victory over a top 100 player.

"I feel amazing, I'm super happy with my performance today, I just tried to have great energy from the beginning and just show I belong here," said Stakusic.

"It's my best victory for sure... the Canadian fans motivated me so much today, and the Spanish fans too, I like any noise. For me it was very motivating."

As impressive as Stakusic was, Masarova made 33 unforced errors and was far from her best.

It left the pressure on team-mate Sorribes' shoulders and perhaps that told as she spurned three set points in the tie-break before Fernandez eventually snatched an exciting first set.

Sorribes failed to convert two more set points in the second set tie-break and Fernandez triumphed.

"There are something that I need to work on but my Canadian team-mates and my Canadian cheering squad here did what they had to do, gave me positivity and helped me in the tough moments," said Fernandez.

"That was extremely tough, I tried to stay focused on just one point at a time."

Eugenie Bouchard and Gabriela Dabrowski polished off the sweep with a 6-2, 7-5 doubles win over Sorribes and Masarova.

France clawed back a point in the doubles against Italy, who also won both their singles rubbers.

Jasmine Paolini beat France's Caroline Garcia 7-6 (8/6), 5-7, 6-4 in a thrilling battle after Martina Trevisan beat Alize Cornet 2-6, 6-2, 6-2, earning Italy the tie.

Garcia and Kristina Mladenovic then earned a 5-7, 6-2, 10-6 win over Trevisan and Elisabetta Cocciaretto.

Four-time winners Italy have now beaten France in five of their last seven meetings, edging this battle between two of the four ever-present countries at the tournament, along with Australia and Great Britain.

Trevisan came back forcefully from a set down to triumph in the first singles rubber.

"I'm very happy to bring the point to my team, when I play for Italy, for my country, it's always special," she said.

Cornet said she was unwell in the second set.

"I was feeling pretty good before and during the first set," she explained.

"Then my form dropped. I started to feel a bit dizzy, and I think she changed her strategy and she played much smarter from the second set."

Paolini and world number 20 Garcia played out a consistent first set with just one break point, which the Italian saved, eventually triumphing in the tie-break.

In the second set Garcia blew two set points at 5-4 up but immediately recovered Paolini's break and made no mistake at the third time of asking, forcing a decider.

However, it was Paolini who emerged victorious in a tense finale, winning the final four games to clinch victory.