Miami: American Sloane Stephens had cause for a double celebration Tuesday after beating Germany's Angelique Kerber 6-1, 6-2 to reach the WTA Miami Open semi-finals.

The US 13th seed's comprehensive triumph in tricky wind conditions over the former world number one ensured Stephens reached the last four at Key Biscayne for the first time.

It also means the reigning US Open champion will finally be named in the world's top 10 when the WTA release their rankings next week.

"I am so tired of hearing that I am number 11 in the world," said a smiling Stephens, who will face either Victoria Azarenka of Belarus or sixth-ranked Czech Karolina Pliskova for a place in Saturday's final.

"It's very exciting to get there, something I have wanted to do for a while. Getting into the top 10 is pretty special and something I have worked on for a long time."

Stephens' previous best here in Key Biscayne came with a quarter-finals run in 2015 so the emotions on display at the end of what was an ultimately straightforward win over the world number 10 were understandable.

Since her debut Grand Slam triumph at the US Open last September, the 25-year-old has struggled to follow on. Stephens arrived at Key Biscayne having not beaten a top-50 player since the run at Flushing Meadows.

But this week has seen the American, who was raised in South Florida, get back to her roots -- and to winning ways. 

Reigning Wimbledon champion Gabrine Muguruza was emphatically dispatched in straight sets Monday before Kerber received similar treatment.

Wind hampered both players but it was Stephens who adapted far better, the power of her groundstrokes and superior movement leaving Kerber frustrated and unable to find a way into the encounter.

"The wind is uncomfortable for both of us. But it can help push you outside of your comfort zone. You just have to embrace it," Stephens said.

Stephens took just 23 minutes to wrap up the first set, Kerber looked sluggish from the start.

Kerber was deep in conversation with coach Wim Fissette during the break, being urged to assert herself.

Kerber saved four break points in the fifth game but Stephens did not allow her opponent into the match and a 22nd winner sealed the triumph.

"You have to execute your game well and make sure you stick with it," Stephens said. "It's easy to start doing other things so I just need to keep to my plan and make sure I didn't venture off."

Kerber admitted coming through a grueling three-set win over qualifier Wang Yafan the day before had left her flat.

"I was really feeling a little bit tired today," Kerber said. "It was windy, it was tricky, but I've played so many matches in the last three months that I was feeling it a little bit in my body."