The 23-time grand slam singles champion Serena Williams will continue her comeback next month, when she plays at the national bank open in Toronto,  in what will be a warm up for a likely participation at the US open.

The 40 year old played in her first singles tournament for a year at Wimbledon where she lost to the unseeded Harmony Tan in the first round.

However, the American has signed up to play at one of the US open warm-up tournaments, beginning on August 8, but did not commit to her future plans.

She has won the US Open six times but is currently unranked having not won a singles match for more than a year.

This year’s US Open begins on August 29.

Williams returned to competitive tennis in the doubles at Eastbourne last month having not played since retiring injured from her first-round match at Wimbledon last year.