Australian Open champion Jannik Sinner reached the Miami semi-finals by ending Tomas Machac's stunning run at the ATP Masters event.

Second seed Sinner used his explosive power and precision to win 6-4 6-2 against his 60th-ranked Czech opponent.

Machac beat Andy Murray and Andrey Rublev to play a first Masters quarter-final but Sinner's level was too good.

The 22-year-old Italian faces Russian third seed Daniil Medvedev or Chile's Nicolas Jarry in the semi-finals.

Sinner won the first Grand Slam title of his career at Melbourne Park in January and has continued his fine form since.

The world number three won another title in Rotterdam before reaching the semi-finals in Indian Wells, where he lost to Carlos Alcaraz for his only defeat of the 2024 season.

Sinner and Alcaraz are forming a burgeoning rivalry and, with the 20-year-old Spaniard playing Bulgaria's Grigor Dimitrov in the last eight on Thursday, they remain on course to meet again in the Miami final.

After recovering an early break of serve against the 23-year-old Machac, Sinner found his rhythm to reach the last four without any further major problems.

He converted four of 11 break points, without facing another himself, to reach the semis for the third time in his career.

"Physically I feel good, I'm just happy to compete," said Sinner, who lost to Medvedev in last year's Miami final.

"We practice very hard to be in these positions and I'm happy to be in the semis again."