World number one Aryna Sabalenka made swift work of her Miami Open match against Zheng Qinwen to cruise into the quarter finals.

The reigning champion took just an hour and 25 minutes to beat her Chinese opponent 6-3 6-4.

Sabalenka, 27, has won the US Open in each of the past two years and looks in serene form. She will face Hailey Baptiste in the last eight after the American defeated Latvian Jelena Ostapenko – also by a 6-3 6-4 margin.

Fourth seed Coco Gauff also reached the quarter-finals with a hard-fought 6-3 4-6 6-2 win over Sorana Cirstea of Romania.

The 22-year-old American served six double faults and was broken five times in a sketchy display, but she had enough to win through and set up a match against Amanda Anisimova or Belinda Bencic.

The Miami tournament is Gauff’s home event and she is eager to win the title but will not be stressing herself over doing so this year.

She came into the event on the back of a retirement at Indian Wells earlier in the month, when a nerve problem in her left arm caused her to abandon a third-round match.

“I don’t really feel pressure, I feel more supported at this event,” she said.

“I want to win this tournament so bad because it is my home tournament. But I didn’t have the best preparation, so setting expectations lower allows me to free up and not expect too much of myself.”