She rediscovered her fire, but world No.1 Serena Williams is still on the lookout for her best form as she attempts to break a five-year drought by winning the upcoming Australian Open.

Williams was well below her best during this summer’s Hopman Cup campaign, with the 18-time major winner complaining of fatigue during the mixed-teams event.

The 33-year-old lost two of her four singles matches, including a 6-4 6-7 (7-3) 6-1 defeat to world No.5 Agnieszka Radwanska in Saturday’s final.

Poland’s team of Radwanska and Jerzy Janowicz won the final 2-1 after prevailing 7-5 6-3 in the deciding mixed doubles, with Williams destroying a racquet and calling the chair umpire a liar during the heated affair.

Williams will now head to Melbourne for a series of practice sessions ahead of the Australian Open, starting January 19.

The American has won the Australian Open five times, but she’s failed to come up trumps since last lifting the trophy there in 2010.

World No.2 Maria Sharapova, Simona Halep, Petra Kvitova and Eugenie Bouchard are among the contenders to take home this year’s crown, while Radwanska is also in with a huge chance following her strong form at the Hopman Cup.

Radwanska beat Casey Dellacqua, Williams, and Heather Watson during the tournament, with her only blemish a hard-fought three-sets loss to Frenchwoman Alize Cornet.

The 25-year-old recently linked with tennis legend Martina Navratilova, and she’s hoping it will prove to be a pivotal step in winning her first career major.

But for now, Radwanska will turn her attention to the Sydney International, where she takes on Cornet in what is expected to be another epic encounter.

“When we play it’s always three hours, so we are laughing that we will try to play less than that this time,” Radwanska said.

Poland’s win was their first Hopman Cup title triumph, making up for last summer’s loss to France.

The tournament was hit by a glut of withdrawals on the men’s side of the field, with Nick Kyrgios, Jo-Wilfried Tsonga, Jack Sock and Radek Stepanek pulling out before the start, and Matt Ebden (calf) lasting just one match.

Nevertheless, a total of 95,742 attended the tournament, well up on last summer’s figure of 84,050.

The Hopman Cup record still stands at 104,468, which was achieved during the tournament’s first appearance at Perth Arena two years ago.