HEATHER WATSON continued her impressive preparation for next week's Australian Open by advancing to the semi-finals of the Hobart International on Thursday.

The British No.1 followed up her victory over fifth seed Sloane Stephens with a 7-6 (7/0) 6-2 win over Italian ninth seed Roberta Vinci and has yet to drop a set in the tournament.

The world No.49 served three aces and won 76 per cent of points on her serve in a hard-fought opening set before racing through the tie-break without dropping a point.

And the statistics were even more impressive in the second, Watson sending down five aces and claiming 84 per cent of points behind her first serve as she broke Vinci three times on her way to victory in an hour and 47 minutes.

Watson will face American Alison Riske in the last four after the eighth seed beat second seed Zarina Diyas 6-3 6-0.

The tournament saw its top three seeds crash out on Thursday, with top seed Casey Dellacqua beaten in the second round before Diyas and third seed Camila Giorgi bowed out in the quarter-finals.

With Wednesday's play wiped out due to rain, both Riske and Diyas had played their second-round matches in the morning, Riske beating Bojana Jovanovski in three sets and Diyas defeating Daniela Hantuchova 7-5 6-1.

In the afternoon session, Japan's Kurumi Nara defeated Giorgi 6-1 3-6 6-2 to book a semi-final with qualifier Madison Brengle, who saw off Dellacqua's conqueror Karin Knapp 6-7 (3/7) 6-4 6-4.

Meanwhile, Liam Broady and Kyle Edmund are both just one match away from qualifying for the Australian Open for the first time after impressive performances in Melbourne on Thursday.

But defeats for Broady's sister Naomi and compatriot Johanna Konta ensured Heather Watson will be the only female British player in the year's first grand slam, which gets under way on Monday.

Liam, 21, edged a fiercely-contested affair with American Jared Donaldson, winning 7-6 (7/4) 6-7 (5/7) 6-4 in a match lasting just over three hours, while Edmund, 20, came from a set down to beat another American, Austin Krajicek, 4-6 7-6 (7/4) 6-2.

"I played a practice set with Jared a couple of days ago so I knew he was a very good player," said Broady, who finished the match in style with back-to-back aces. "I expected myself to win but he put up a massive fight, especially on massive points. But I stayed strong in the end and came through it.

"I had really high expectations coming in because I finished last year strongly and it would mean the world to qualify for my first grand slam."

Broady will face American Michael Russell in the final round of qualifying on Saturday, while Edmund takes on Australian Dane Propoggia.