The world No. 2, who had suffered a slump since her early exit from Wimbledon last month, comfortably outsmarted the former Cincinnati champion, winning 6-4 6-1 in one hour and 27 minutes on Wednesday.

It was Barty's 40th win of the season, with her win-loss record 40-7, leaving her second only to Dutch ace Kiki Bertens (41-16).Sharapova says the Australian's tricky arsenal reminds her of Belgian great Justine Henin.

"Not an easy match and really not an easy match-up for me. I think she does a lot of things well. She's a tricky opponent," she said.

"If I had played against her best game like when I was just coming up, like a Henin or someone that sliced and diced and had a lot of variety, it was very tough for me."

Barty will next face Anett Kontaveit after the Estonian beat Pole Iga Swiatek 6-4 7-6 (7-2).

The Australian, keen to avoid a second consecutive opening defeat after her loss to Sofia Kenin in Montreal last week, kicked off proceedings by taking a 1-0 lead.

But Sharapova saved two break points before Barty's errors allowed her to level at 1-1, before surging to a 3-1 lead.

The French Open champion then brought the Russian to the net before smashing a backhand across the court to make it 3-2.Sharapova's errors levelled it at 3-3, with Barty then following a sublime backhand slice with a forehand winner to make it 4-3.

Sharapova levelled again but Barty served it out to lead 5-4 before the Russian put the ball over the baseline to hand her the first set.

Barty raced to a 3-0 lead in the second, but Sharapova pulled one back before over-hitting a return to put the Australian up 4-1.

The world No. 2's drop shot brought Sharapova to the net, before she exquisitely lobbed the ball back inside the Russian's baseline to make it 5-1.

The 23-year-old then served it out for the win.