Slovakia's world number six Dominika Cibulkova dropped just two games in blistering heat to win her opening match at the Sydney International on Monday.

Novak Djokovic said he did not intentionally hit a ball into the crowd during his Qatar Open final against Andy Murray, an incident which threatened to take the gloss off his victory.

World number one Andy Murray claimed his 26th consecutive victory on Wednesday with a battling 7-6 (8/6), 7-5 win over Austria's Gerald Melzer to reach the Qatar Open quarter-finals.

Serena Williams suffered a shock second-round defeat at the Auckland Classic Wednesday following her sister Venus's earlier withdrawal with an arm injury.

Andy Murray began 2017 where he left off last year, beating Jeremy Chardy in straight sets in his season opener in Qatar on Tuesday to register his 25th consecutive victory.

World number one Andy Murray insisted Sunday that Novak Djokovic will remain his biggest threat in 2017, as the pair prepare for a potential first clash of the season in Doha this week.

Former world No 1 Ana Ivanovic on Wednesday announced her retirement from tennis, admitting that the physical toll of the circuit had proved too much.

On-going fitness issues have forced Juan Martin del Potro out of next month's Australian Open and his planned warm up event in New Zealand, organisers of the Auckland Classic announced Saturday.