World number one Iga Swiatek knocked out of US Open by Jessica Pegula

World number one Iga Swiatek was sent crashing out of the US Open on Wednesday by Jessica Pegula who moved into her first Grand Slam semi-final.

Sixth-ranked Pegula triumphed 6-2, 6-4 and will face Karolina Muchova of the Czech Republic for a place in Saturday's final.