World No.1 Serena Williams of the US stormed in to the US Open women's singles semi-finals with a facile 6-3, 6-2 win over Flavia Pennetta of Italy here.
The American tennis star Wednesday moved within two wins from her sixth US Open title. She will play Ekaterina Makarova of Russia in the semis, reports Xinhua.
Pennetta was once leading 3-0 in the first set, but Williams won the next six games in a row to claim the first set.
Pennetta failed to come back in the second set, allowing Williams to break twice to seal the victory.