Postpublished at 05:04 Greenwich Mean Time 29 January 2015
A delicious lob, disguised beautifully, from Williams hauls the American back to 30-30. An 122mph ace - her fastest serve so far - brings up game point but Keys forces deuce with a backhand winner down the line.
But Williams clings on to win the next two points and seal the game. Keys to serve to stay in the set once more.