WASHINGTON: Former world number ones Maria Sharapova and Venus Williams were given wildcard entries into next month's WTA Cincinnati tournament, a key tuneup event for the US Open.

Each will compete in the main draw for the August 12-18 hardcourt event.

Sharapova is one of only six women to have completed a career Grand Slam. The 32-year-old Russian owns 36 WTA titles, including five Grand Slam crowns, and is ranked 81st in the world. Her most recent Grand Slam title came at the 2014 French Open.

She suffered a nagging shoulder injury and missed more than four months before returning on grass, but retired in the third set of her opening-round match at Wimbledon.

Sharapova won the 2011 Cincinnati title and lost in the 2014 semi-finals in her most recent appearance.

Williams, 39, has won seven Grand Slam titles among her 49 WTA crowns and has finished runner up in Grand Slams another nine times. The 51st-ranked US star won singles gold at the 2000 Sydney Olympics and has won three Olympic doubles titles with sister Serena.

It will be Venus's seventh Cincinnati start in her 25-year WTA career, her best run came in 2012 when she lost in the semi-finals.

Williams, a five-time Wimbledon singles champion, lost to US 15-year-old qualifier Coco Gauff in the first round at Wimbledon in her most recent start.

"Maria and Venus are two of the greatest champions in tennis history," tournament director Andre Silva said. "We look forward to both joining our world class field."