Wildcard Nick Kyrgios needed just 51 minutes to stun world No.7 Andrey Rublev 6-3 6-0 and move into the last 32 of the Miami Open.

No.5 seed Rublev looked good at the start, building a 2-1 lead after breaking the Canberran in the early stages of the first set in Friday’s match.

But it was all downhill from there for the Russian as Kyrgios piled up the winners and put pressure on Rublev’s serve by stepping into the court to take the ball early.

“I don’t think I played unbelievable, I just played the right way,” Kyrgios told Tennis Channel.

“Against Rublev, you know he wants to try and dictate, to have a lot of rhythm, and I didn’t give him that today.

“I tried to slap as many winners as I could, serve well and get up the court on my return and it worked.”

The win will see Kyrgios rise further from his world ranking of No.102 and comes immediately after he was handed a $25,000 ($A33,000) fine for almost hitting a ball boy with his smashed racket at the Indian Wells tournament. 

Kyrgios, who has won five of his last six matches, will next play Italian Fabio Fognini, who beat Japan’s Taro Daniel 6-7 (7-1) 6-2 7-6 (7-5) earlier in the day.

Alexander Zverev’s superior serving led to a 6-4 3-6 6-3 win over Borna Coric in their second-round match.

Zverev, having split the first two sets against Croatian Coric, served his way out of trouble in the first game of the third set and fended off a break point while serving up 5-3 en route to the hard-fought win.

The German, who fired down 12 aces and only committed one double fault, said his more aggressive approach was the difference in the contest.

“The last few matches I was losing close three-set matches because I felt I wasn’t going for it,” said Zverev, who fell to Tommy Paul in a tight three-setter in the second round of Indian Wells earlier this month.

“Today I felt like if I’m going to lose, I’m going to go for it. That worked out and hopefully it will in the next match as well.”

Zverev will next meet either American Mackenzie McDonald or Bulgarian Grigor Dimitrov.

Italy’s ninth seed Jannik Sinner beat Emil Ruusuvuori of Finland in the best match of the tournament so far, rifling a forehand service return winner to seal a 6-4 3-6 7-6 (10-8) victory.

World No.11 Sinner will next face Pablo Carreno Busta, who beat David Goffin of Belgium 6-3 6-2.

Frenchman Hugo Gaston overcame 22 aces from American John Isner to advance 7-6 (7-5) 6-4 and 10th seed Cameron Norrie defeated compatriot Jack Draper 7-6 (7-5) 6-4 at the Masters 1000 tournament. 

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