Germany’s Tommy Haas has withdrawn from the Brisbane International with a calf injury.
The former world No.2 was due to play Denis Istomin of Uzbekistan for a place in the quarterfinals, but he was forced to pull out at the beginning of day four.
Istomin now moves into the quarterfinals where he will play either eighth seed Bernard Tomic or Tatsuma Ito.
He has also withdrawn from the doubles as well. Haas and partner Radek Stepanek were due to play top seeds Max Mirnyi and Daniel Nestor today. Mirnyi and Nestor have been elevated straight into the semifinals.
Some tickets still remain for the day and night sessions at Pat Rafter Arena. Tickets can be purchased online from Ticketek.