Sinner survives scare to advance in Miami Miami, United States

The second-seed Italian, a two-time finalist in Miami, struggled against Griekspoor's power play in the first set but turned the contest around after a rain break at 3-3 in the second set.

Sinner came out fighting and took the second before utterly dominating the third to book his place in the last 16.

"I think even the first set was really close, but it (got) away," said Sinner.

"I think mentally I tried to stay strong, which I did, and I was in a tough situation today. After the rain came, I tried to come back a bit more aggressive, which I did, and obviously I'm really happy. It has been a tough day for me, but very happy about the result."

Sinner will face Australian Christopher O'Connell, who emerged with a tight win over the USA's Martin Damm 7-6 (7/5), 7-6 (7/5).

Reigning champion Daniil Medvedev beat Britain's Cameron Norrie 7-5, 6-1 and while he was happy with his performance he said that rapidly deteriorating balls were creating unusual games.

"It's a bit strange. The court is pretty fast but the balls get old very fast. So at one moment in the rally, you feel like there isn't much you can do. So you can't go for the winner because the risk reward isn't there. It's the same for the opponent, so we just hit, hit," he told reporters.

There was an atmosphere akin to a South American World Cup football match for the clash between Chile's 22nd-seeded Nicolas Jarry and Brazilian qualifier Thiago Seyboth Wild.

After upsetting American Taylor Fritz on Saturday, Seyboth Wild was hoping for another scalp and he pushed the more experienced Jarry hard in front of a packed mostly South American crowd on the third court.

Jarry's staying power proved decisive as he ran out 6-7 (1/7), 7-5, 6-3 winner.

Hungarian Fabian Marozsan upset world number seven Holger Rune with a 6-1, 6-1 triumph in the second round.

The convincing victory, in just 59 minutes, was a third win against a top-10 opponent in a Masters event for the 57th-ranked 24-year-old.

Marozsan dominated his Danish opponent from the outset, striking 23 winners and saving all three break points that he faced.

The Hungarian's two previous wins against top-10 opponents at this level came when he beat Carlos Alcaraz in Rome and Casper Ruud in Shanghai last year.

"I enjoy playing at the highest level. I had a great day and enjoyed every moment on the center court against a very talented player," said Marozsan.

"I tried to put more pressure on him and I played very high intensity tennis and maybe he didn't find the way to come back or do something different."

Marozsan will face Alexei Popyrin in the third round after the Australian beat Czech Jiri Lehecka 6-4, 6-4.

- Shelton fights through -

After three of the four top-ranked Americans exited the tournament on Saturday, Ben Shelton kept the Star Spangled flag flying in Florida with a 6-3, 6-4 win over Spanish teenager Martin Landaluce.

Shelton did not face a break point in the contest and won both sets with unstoppable aces down the middle.

"I thought I was pretty complete today,” said Shelton. "I thought I did a great job backing up my serve and usually when I have a lot of confidence and holding easily, the rest of my game continues to flow, and my confidence just grows.

"I think that helps me a lot and puts a lot of pressure on the other guy."

In the third round, Shelton will be against 23rd seed Italian Lorenzo Musetti, who defeated Russian Roman Safiullin 7-5, 6-1.