MIAMI (REUTERS) - American Sloane Stephens needed just over an hour to cruise past Germany's former world number one Angelique Kerber 6-1 6-2 and reach the Miami Open semi-finals for her first time on Tuesday (March 27).

The US Open champion fired her 22nd winner on match point to dispatch the 10th-seeded Kerber and set up a showdown with either Karolina Pliskova or Victoria Azarenka, who play their quarter-final later on Tuesday.

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

Tuesday's win was Stephens' second straight triumph over a former world number one after she defeated third-seeded Garbine Muguruza to reach the quarter-finals on Monday.