Polish teenager Agnieszka Radwanska caused her second big shock in as many days when she stunned Russian top seed Elena Dementieva 7-5, 6-2 in the quarter-finals of the Luxembourg Championship on Friday.

In the semi-finals the teenager will play Italian fifth seed Francesca Schiavone, who outclassed third seed Patty Schnyder 6-1, 6-1.

A day after ousting an injured Venus Williams, the 17-year-old Radwanska took advantage of seven double faults from Dementieva to reach her first WTA Tour semi-final.

Dementieva led by an early break but the 95th ranked Radwanska hit back, breaking in the 12th game to take the opening set.

The Pole raced to a 3-0 lead in the second set and though Dementieva broke back, Radwanska moved ahead again and clinched victory by breaking Dementieva for the seventh time in the match.

On a bad day for the Russians, fourth seed Dinara Safina was also shown the exit when she was beaten 6-4, 6-3 by Czech Kveta Peschke.

Peschke will meet unheralded Ukrainian Alona Bondarenko in the last four after the 22-year-old ousted Nathalie Dechy of France 5-7, 6-4, 6-0.