SYDNEY, Australia - Always dangerous when drawing big names, Camila Giorgi lived up to her giant-killing reputation at the Apia International Sydney, shocking last year's US Open champion Sloane Stephens, 6-3, 6-0.

The Italian ended her 2017 season after the US Open, but looks to be enjoying strong form in the new year, reigning in her high-octane game to manage 21 winners to 20 unforced errors, barreling through the win in 65 minutes on Ken Rosewall Arena.

Stephens was playing her first event of the season, and despite keeping with the Italian through the first five service games, she was clearly troubled by Giorgi's relentless pace, striking 35 unforced errors to 23 winners and falling to 0-7 (including Fed Cup) since capturing her maiden Grand Slam title in Flushing Meadows.

Afterwards, the American said that she had not yet recovered from a shortened off season: "I didn't even play the whole season and I'm already burnt out the first week," she told the press.

"Playing Fed Cup final, that was, like, a little bit longer than the other girls. It's not easy, and it just keeps getting longer and longer."

However, she was positive regarding the condition of her knee, which had forced her to withdraw from the Brisbane International last week: "Tough day today, but all in all, everything is looking up. Looking forward to getting to Melbourne and playing there."

Monday's win marks Giorgi's 23rd against a Top 20 player, and her first since Wimbledon, where she outlasted future US Open runner-up Madison Keys in three sets.

Standing between the Italian and a spot in the quarterfinals will be the winner of a big-hitting battle between two-time Wimbledon champion Petra Kvitova, who led Australian Open semifinalist Mirjana Lucic-Baroni by a set before the Croat was forced to retire due to illness.