Iga Swiatek sealed the 'sunshine double' with a trouncing of Naomi Osaka as the new world number one added the Miami Open title to her Indian Wells triumph.

Twenty-year-old Swiatek will succeed the retired Ash Barty on top of the WTA rankings on Monday, and she has reached the top spot for the first time in staggering style.

A 6-4 6-0 victory against former number one Osaka in Saturday's final made Swiatek the first player to win the first three WTA 1000 events in a season.

Those are the highest value tournaments on the tour outside the grand slams, and Swiatek has chopped down the fields in Doha, Indian Wells and now Miami in staggering fashion.

Her winning streak stands at 17 matches, her record for the season is 26-3, and she has won 20 consecutive sets.

Swiatek set the tone for the match when she broke for a 3-2 lead in the opening set, whipping an exquisite backhand winner across court to seize the initiative.

She had a look-in next time around too, with Osaka doing well to fend off a break point and keep the Pole within touching distance.

The first set was secured when Osaka hoisted an aggressive forehand service return long, and that ramped up the pressure at the beginning of the second

In a flash, Swiatek earned herself three breakpoints, and although Osaka saved the first with a drive volley, the Japanese player sent a forehand into the net on the next point

Swiatek was displaying some startling shot-making, and a cross-court forehand winner in the third game was a thing of beauty, helping her establish a double break.

Osaka is battling her way back into the sport after documenting her struggles with mental health and depression, and her ranking stood at 77 before this tournament.

By reaching the final she proved her talent remains formidable, but Swiatek at present is on another level to her tour rivals, and a clinical sweep of the second set was complete when Osaka hooked a forehand wide.

Only three players had previously secured this back-to-back double in Miami and Indian Wells: Steffi Graf in 1994 and 1996, Kim Clijsters in 2005 and Victoria Azarenka in 2016. Swiatek is the youngest to achieve the feat.