Nick Kyrgios and Naomi Osaka seal comfortable wins in Miami Open first round

Australian Nick Kyrgios sealed a comfortable victory over Frenchman Adrian Mannarino in the first round of the Miami Open on Wednesday, while former world No 1 Naomi Osaka defeated Astra Sharma.

Wildcard Kyrgios fired down 12 aces and did not face a single break point in his 7-6, 6-3 win.

"It was a hell of a performance," Kyrgios said. "Getting on late, it wasn’t easy. So I'm really proud of myself with the way I responded. I felt good, I competed well today against a tough opponent."

The Australian said he would be a "complete underdog" in his second-round match against Russian fifth seed Andrey Rublev. "But I feel confident. If I'm serving well and play well from the back, I can beat anyone," he added.

Earlier, Osaka was cheered on to a 6-3, 6-4 win over Australia's Sharma.

Osaka was in complete command right from the moment she stepped onto the Hard Rock Stadium court, never allowing Sharma a single break opportunity while keeping her 96th-ranked opponent under constant pressure, converting two of 11 break points.

After the match, Osaka soaked up the applause from the sparse crowd in what was a far different atmosphere from 11 days earlier in Indian Wells when she fought back tears after being heckled during a second-round loss to Veronika Kudermetova.

"This is like my home tournament," said Osaka during her on-court interview, prompting a round of cheers. "Honestly I just didn't want to let anything bother me today no matter what happened, like the last match I played was not the greatest memory for me.

"I just wanted to prove I could come back out here and compete and no matter if I won or lost just know I had the best attitude that I could."

A four-time Grand Slam champion, Japan's Osaka has seen her ranking fall