Serena Williams has kept alive her dream of winning all four Grand Slams in a year by beating sister Venus Williams 6-2 1-6 6-3 in the quarter-finals of the US Open.
The pair have eight singles titles between them at Flushing Meadows, but it is Serena who remains in contention to clinch her seventh triumph in New York after a dramatic clash.
In an encounter full of powerful winners from both players, there was no breakthrough until the fifth game of the opener when a couple of errors from Venus handed the early advantage to the world number one.
Serena then started to dominate from the baseline, and the younger sibling took charge of the longer rallies to break once more before wrapping up the first set.
Venus recovered impressively on serve to give her sister very little chance of running away with the match and after some strong returns of serve, the 23rd seed broke thanks to a double fault.
As support grew for the two-time winner, Serena was showing signs of the pressure getting to her at the other end of the court and she struggled to change the momentum as more sloppy errors gifted a second break to Venus.
A shock appeared to be on the cards after such an emphatic fightback in the second set from Venus, but the response from Serena was swift in the early stages of the decider as she unleashed a couple of stunning winners from the baseline to earn a break and race into a 3-0 lead.
Serena's difficulties from the second set seemed to be behind her as she attacked with her trademark power on both sides throughout the third, and the top seed secured an emotional win to set up a semi-final clash with unseeded Italian Roberta Vinci.