World number five Juan Martin del Potro, the man tipped to challenge for grand slam titles this season, began his year with a scrappy win over Frenchman Nicolas Mahut to advance to the quarter-finals of the Sydney International yesterday.

The Sydney warm-up to the Australian Open has proved a graveyard for the seeds this week but the 25-year-old avoided an early flight to Melbourne by coming back to win 1-6 6-3 6-4.

Rated a dark horse to win the title at Melbourne Park and add to his sole grand slam triumph at Flushing Meadows in 2009, the top seeded Argentine will next take on Czech veteran Radek Stepanek for a place in the last four.

Other seeds struggled, with no.3 Andreas Seppi from Italy bundled out by Australia’s Marinko Matesovic 6-3 6-4 and sixth seed Julien Benneteau, of France, dumped in straight sets by Sergiy Stakhovsky.

Defending champion Bernard Tomic advanced with a hard-fought 6-3 4-6 6-4 win over Slovenian qualifier Blaz Kavcic, continuing his habit of raising his game for home fans at the start of the year.

The rangy 21-year-old, ranked 52nd in the world, has disappointed some in Australia for failing to live up to sky-high expectations and has been drawn into controversy by his coach and father John Tomic.

Tomic senior has been barred from the Australian Open after a court in Spain convicted him of assaulting his son’s former hitting partner last year.

“The majority of the crowd like me in Australia,” Tomic told re-porters after setting up a quarter-final with Ukraine’s Alexandr Dolgopolov, yesterday.

“At the end of the day, if you win, it’s going to put a zip to everyone I guess.”

The women’s draw, which has already seen top seed Agnieszka Radwanska and former world no.1 Caroline Wozniacki sent packing, lost third seed Sara Errani, last year’s surprise French Open semi-finalist, who was upset 7-6 6-3 by Bulgaria’s Tsvetana Pironkova in the quarter-finals.

The Italian world number seven took a medical time-out in the second set to have treatment on her lower back, raising concerns over her fitness ahead of the year’s first grand slam.

Former Wimbledon semi-finalist Pironkova will play second seed and former Wimbledon champion Petra Kvitova, who wore down Lucie Safarova 7-6 6-2, for a place in the final.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.