Andy Murray seeded fifth for Australian Open

• Judy and Andy Murray host a coaching clinic in Melbourne ahead of the Australian Open which starts next week. Picture: Getty Images

The British No 1 reclaimed the No 4 spot with his run to the semi-finals of the Barclays ATP World Tour Finals in London in November, but Soderling's victory at the Brisbane International on Sunday means they have swapped places again.

Murray has also been in good form, winning all three of his singles matches at the Hopman Cup last week, but the 23-year-old has paid the price for the team tournament not being a ranking event.

Murray - who took part in a coaching initiative with mother Judy in Melbourne yesterday - was well aware of the potential implications of his decision to play in Perth, having been usurped by Juan Martin Del Potro in similar circumstances last year.

The drop means he could find Novak Djokovic, Roger Federer and Rafael Nadal all blocking his path to a first grand slam title when the draw is made on Friday. The tournament starts on Monday.

Murray's Hopman Cup playing partner, Laura Robson, was forced out of the Australian Open yesterday through a thigh injury. The 16-year-old prospect suffered the injury at the Hopman Cup and has now been told she needs three weeks on the sidelines. She had been due to take her place in the Australian Open qualifying tournament but will instead take treatment at her Paris training camp.

Patrick Mouratoglou, Robson's new coach, said: "The envelope surrounding the muscle is torn. She needs three weeks to recover well, so we decided not to play the Australian Open. If she had played qualifiers it would have been very dangerous. She could have torn the muscle and she would then have been out for six to ten weeks, so it would have been stupid. She's upset but she's OK. She's going to play many other Grand Slams."

The injury also means Robson will not play in Britain's Fed Cup team in Israel in February.

British No 1 Elena Baltacha, meanwhile, is through to the second round of the Hobart International after a 6-3, 6-3 victory over world No 64 Tamarine Tanasugarn of Thailand.

The 27-year-old Scot, now ranked 55th in the world, faces Roberta Vinci, of Italy, in the second round this morning as she continues her preparations for the Australian Open.

Baltacha, playing in her first competitive match of 2011, displayed signs of rust, particularly with her serve, and was broken twice in the second set. However, she declared herself satisfied with her performance. "Obviously, the first match of the year, having not played a match in two months, it's always quite difficult," said Baltacha. "But I managed that very well. I was really confident and I enjoyed the battle and obviously I was delighted that I managed to win it."I knew I had to be aggressive and really take the match to her, which I managed to do."

"It was always helps when you do well at the beginning of the year. I did that last year. I came out to Australia and I qualified for my first two tournaments and then made the third round of the Australian Open."

Defending champion and second seed Marcos Baghdatis pulled out of the Sydney International yesterday with a groin strain. The Cypriot, beaten finalist at the 2006 Australian Open, said he did not want to risk worsening the problem before the opening grand slam of the year.