Ekaterina Alexandrova pulled off another surprise victory to book a semi-final clash with unseeded Danielle Collins in the Miami Open.

The 14th seed, followed up her victory over world number one Iga Swiatek, by beating fifth seed Jessica Pegula 3-6 6-4 6-4.

The win, which took just under two hours, ensured the 29-year-old's second WTA 1000 event semi-final appearance.

Collins reached the last four in Miami for the second time with a 6-3 6-2 win over 23rd seed Caroline Garcia.

Six years after becoming the first qualifier to reach the semi-finals, the 31-year-old former Australian Open finalist did not face a break point as she earned a third win over a seed in five matches.

In her final year on tour, Collins has won 10 straight sets since losing her first of the tournament, dropping just 19 games along the way.

Fourth seed Elena Rybakina faces three-time Miami champion Victoria Azarenka in the first of Friday's semi-finals.