Elena Dementieva has won her Wimbledon quarter-final in straight sets. The Russian fourth seed came through 6-2, 6-2 against Francesca Schiavone of Italy. Defending champion Venus Williams is through to the semi-finals of Wimbledon's ladies singles. She blitzed Agnieszka Radwanska of Poland 6-1, 6-2. Dinara Safina had to come back from a set down for the second day running. But the top seed's through to the semi-finals after a 6-7, 6-4, 6-1 win over German teenager Sabine Lisicki.