Wimbledon 2013: Madison Keys is locked out of further progress by Agnieszka Radwanska

Pole star: Agnieszka Radwanska ends the hopes of America’s Madison Keys (Getty Images)

Madison Keys, the promising American teenager, saw her run at Wimbledon ended by the fourth-seeded Agnieszka Radwanska.

The 19-year-old was the subject of plenty of attention at the All England Club in the first week after beating Heather Watson, Britain's No 2, and then the seeded Mona Barthel, but she was unable to make it into the second week. Keys more than held her own over two sets against last year's finalist, losing the first set 7-5 before taking the second 6-4. But she was unable to maintain the standard in the third and her serve was broken in the sixth game to give Poland's Radwanska a lead she would not surrender.

Keys at least staved off match points in the seventh game, forcing Radwanska to serve out for a 6-3 win and set up a clash with Tsvetana Pironkova, who beat Petra Martic.

Petra Kvitova, the 2011 champion, showed impressive character to avoid becoming another high-profile first-week casualty.

It had looked like the pattern of underachievement by top-10 seeds would continue, with Kvitova in big trouble after the second set against Ekaterina Makarova, only for the eighth seed to win 6-3 2-6 6-3.

Bad light and rain had halted them on Friday, and their third-round clash resumed on Court One yesterday with Makarova, the world No 27, a break up at 2-1 in the decider. It had looked like a tough job awaiting the former world No 2, but it was a challenge she tackled eagerly. Kvitova dug deep to take a topsy-turvy third set and secure a last-16 clash with Spain's Carla Suarez Navarro.

In another rearranged match, Sloane Stephens, the 17th seed, beat Petra Cetkovska, a Czech qualifier, 7-6 0-6 6-4.

The American will face Monica Puig in the fourth round after the Puerto Rican recovered from a set and a break down against Eva Birnerova to win 4-6 6-3 6-4.