US Open finalist Roberta Vinci's preparations for the first grand slam of the 2016 season suffered a blow on Monday as she fell at the first hurdle in the Apia International, losing 4-6 7-5 7-5 to Samantha Stosur.

Vinci lost out to compatriot Flavia Pennetta at Flushing Meadows having seen off Serena Williams in the semi-finals, and will be looking to build on that performance this year, beginning at the Australian Open.

However, after getting the better of Stosur in a scrappy opening set, Vinci was unable to capitalise on an early break in the second as the Australian restored parity.

Vinci then fell behind early in the decider and squandered numerous opportunities to draw level before eventually succeeding to make it 5-5.

But after going 6-5 down on her opponent's serve, Vinci was broken to love to bring a disappointing end to her campaign.

Vinci's fellow Italian Sara Errani faced no such problems as she saw off seventh seed Carla Suarez Navarro 6-3 6-3, while Ekaterina Makarova breezed past Lucie Hradecka 6-2 6-1.

There was another comfortable win for Sabine Lisicki against Polona Hercog, prevailing 6-4 6-3, and Angelique Kerber came from behind to beat Elina Svitolina 4-6 6-0 6-3.

Elsewhere, Anastasia Pavlyuchenkova, Monica Puig and Belinda Bencic all booked their place in the second round with victories over Lara Arruabarrena, Magdalena Rybarikova and Mirjana Lucic-Baroni respectively.