Stephens, Azarenka in Miami semis showdown

Sloane Stephens has needed just more than an hour to cruise past former world No.1 Angelique Kerber 6-1 6-2 and reach the Miami Open semi-finals for the first time.

The US Open champion fired her 22nd winner on match point on Tuesday to dispatch German 10th seed Kerber and set up a showdown with three-time champion Victoria Azarenka, who scored a 7-5 6-3 victory over world No.6 Karolina Pliskova.

The win guarantees 25-year-old Florida native Stephens will make her debut in the top 10 when the WTA rankings are released after the tournament.

The win was Stephens' second straight triumph over a former world No.1 after she defeated third-seeded Garbine Muguruza to reach the quarter-finals on Monday.

Stephens said staying consistent was the key to her win over Kerber.

"When you play a player like Angie you have to execute your game well," Stephens said.

"And then you have to make sure that when you are executing your game you stick with it. Like a lot of times you can venture off and start, you know, doing other things."

Azarenka continued her strong run in Miami where she has now won 11 straight dating to her 2016 title triumph.

Azarenka, who broke Pliskova seven times, will play in her first semi-final in two years.

The former world No.1 was absent from the game for eight months due to a custody dispute involving her son.