Halep of Romania is back in action after overcoming a calf muscle tear which sidelined her for three months.

Her first competitive match since that injury ended in defeat as she went down to Danielle Collins of the United States at the Canadian Open in Montreal.

But Halep, a three-time runner-up in Cincinnati, ensured she was back to winning ways as she battled past Poland’s Magda Linette 6-4, 6-3, 6-1 in two hours and 10 minutes.

Halep revealed she experienced a "sharp pain" in her right leg and "a contracted muscle" which forced her to receive medical treatment in the second set.

There was also a lengthy rain delay in the match, but 12th seed Halep dug deep to seal her place in the second round.

Halep will next face Jessica Pegula of the US who completed a convincing victory over Italy’s Camila Giorgi.

The Italian claimed the biggest title of her career on Sunday (August 15) when she earned the Canadian Open crown with victory over world number six Karolína Plíšková of the Czech Republic.

But Giorgi was unable to back that success up as she was defeated 6-2, 6-2 by Pegula.

Australia’s top seed Barty was scheduled to meet Britain’s Heather Watson today, but the match has now been moved to tomorrow after it was hit by two rain delays.

American teenager Coco Gauff set up a blockbuster showdown with second seed Naomi Osaka of Japan after thrashing 35-year-old Hsieh Su-Wei of Chinese Taipei 6-1, 6-2.

"I think I did well just focusing on my side of the court," said Gauff.

"She hits a crazy shot, and trying to not let that get into my head, because she's talented and she will hit great shots."

Australian Open semi-finalist Karolína Muchová of the Czech Republic came back from a set down to beat Britain’s Johanna Konta 3-6, 7-6 (7-5), 6-2.

Bernarda Pera of the US saw off Sweden’s Rebecca Peterson 6-4, 6-1, Elena Rybakina of Kazakhstan overcame Australia’s Samantha Stosur 6-3, 6-3 and 

Veronika Kudermetova of Russia downed Italy’s Jasmine Paolini 6-3, 6-2, while Tunisia's Ons Jabeur came out on top against Estonia's Anett Kontaveit, claiming a 6-2, 4-6, 7-5 victory.

In the men’s event, Wimbledon runner-up Matteo Berrettini of Italy was pushed all the way before triumphing 6-7 (5-7), 6-3, 7-5 against Albert Ramos-Vinolas of Spain.

Sebastian Korda of the US continued his impressive year by beating Serbia’s Laslo Đere 6-4, 6-4 to secure a second-round clash with Greek second seed Stefanos Tsitsipas.

Bulgaria’s former champion Grigor Dimitrov produced a dominant display to sweep aside 13th seed Roberto Bautista Agut 6-3, 6-4.

"I am very very happy," said Dimitrov, a winner of the Association of Tennis Professionals Masters 1000 title in 2017.

"He is such a tough opponent, but I served really well when I had to."

Dimitrov will now face Kazakhstan’s Alexander Bublik who beat American qualifier Marcos Giron 3-6, 6-3, 7-6 (7-5).

As well as Korda, there were victories for two more home players with John Isner edging Britain’s Cameron Norrie 4-6, 7-6 (7-5), 6-4 and Reilly Opelka outlasting France’s Corentin Moutet 7-6 (7-3), 4-6, 6-4.

Ninth seed Hubert Hurkacz of Poland emerged victorious in a three-set battle with Spain’s Alejandro Davidovich Fokina, winning 6-1, 6-7 (3-7), 6-1.

Italy’s Lorenzo Sonego claimed a 6-3, 7-6 (8-6) victory over Spain’s Carlos Alcaraz, Croatia’s Marin Cilic beat Russia’s Aslan Karatsev 7-5, 6-3 and France’s Gael Monfils proved too strong for Dušan Lajović of Serbia, triumphing 7-6 (7-0), 6-2.

Competition is due to continue tomorrow.