Jack Sock stunned top seed John Isner in the quarter-finals of the ATP Hall of Fame Tennis Championships in Newport.
Stan Wawrinka is a Grand Slam champion after beating Djokovic and Nadal in Melbourne. The 2015 Australian Open will take place from 19 January to 1 February. For information visit the official Australian Open site.
Defending champion Carlos Berlocq upset top seed David Ferrer to move into the semi-finals of the Swedish Open.
Simona Halep eased into the semi-finals of the Bucharest Open with a straight-sets win over Lara Arruabarrena.
Top seed and defending champion Fabio Fognini has booked his place in the semi-finals of the ATP Mercedes Cup.
Shelby Rogers reached her first WTA Tour semi-finals with another convincing win in the Nurnberger Gasteinladies.
Lindsay Davenport and Briton John Barrett will be inducted into the International Tennis Hall of Fame this weekend.
Sam Groth beat defending champion Nicolas Mahut at the Hall of Fame Championships to reach his first ATP semi-final.
Serena Williams has withdrawn from next week's Swedish Open as she has not fully recovered from her Wimbledon illness.
Louk Sorensen's run at the MercedesCup in Stuttgart was brought to an end as he was beaten by Roberto Bautista Agut.
The singles champions at this year's US Open will earn US$3million for their efforts.