Italian 10th seed Jannik Sinner downed Emil Ruusuvuori to secure his berth in the Miami Open semi-finals along with bringing up his 20th win of the season on Wednesday.

Sinner, who dropped only one point on first serve, won 6-3 6-1 over the Finn in one hour and 16 minutes.

The 21-year-old Italian will face either top seed and defending champion Carlos Alcaraz or 2022 Indian Wells winner Taylor Fritz in the last four. Sinner lost to Alcaraz in the Indian Wells semi-finals a fortnight ago.

Alcaraz and Fritz's Miami quarter-final was postponed to Thursday with persistent rain forcing the evening session in Miami to be cancelled.

The other quarter-finals between 14th seed Karen Khachanov and 25th seed Francisco Cerundolo along with fourth seed Daniil Medvedev and qualifier Christophr Eubanks were also re-scheduled for Thursday.

The Sinner-Ruusuvuori clash was also impacted by a two-hour rain delay, but the Italian prevailed to maintain his perfect record in Miami, having not dropped a set.

"We both played well today but I won the important points," Sinner said. "It's never easy when you are up and you get interrupted, but I came back and played well."

Sinner's run to the Miami semi-finals has seen him drop the fewest games (23) since Rafael Nadal (21) and Novak Djokovic (23) in 2014.

The Italian became the seventh male to reach the semi-finals at both Indian Wells and Miami in a single year before turning 22, joining an elite list in Andre Agassi (1990), Jim Courier (1991), Djokovic (2007), Andy Murray (2007 and 2009), Nadal (2008) and Alcaraz (2022).

Sinner's 2023 record is now 20-4, bettered only by Medvedev (26-3) and Cameron Norrie (21-5).