Madison Keys books Serena Williams date after Agnieszka Radwanska scalp

Madison Keys has advanced into the fourth round of the US Open for the first time with a straight-sets win over Agnieszka Radwanska this morning.

The youngster needed a little over an hour to beat Radwanska 6-3 6-2 to set up an all-American clash with world number one and defending champion Serena Williams next.

Keys - ranked 19th in the world, four places below the Pole - became the first woman in this year's edition of the competition to take a set off the former Wimbledon finalist.

She broke Radwanska in the opening game to get off to a dream start, before pulling out another in the ninth to draw first blood against the pre-match favourite.

Radwanska gave Keys a dose of her own medicine by breaking in the first game of the second set to move into an early 1-0 lead as she set off on the comeback trail.

However, the 20-year-old hit back strongly as she broke twice against the serve en route to a 4-1 lead, with two games separating her from the fourth round.

From there, Keys, who reached the Australian Open semi-final earlier this year, never looked in danger as she closed out the match with ease to book a date with Williams.