Andrea Petkovic has already beaten Caroline Wozniacki once in a hard-court tournament this season and she can do so again to reach the semi finals of the US Open.
Petkovic’s victory over the world number one in Miami was a shade unexpected, but a Flushing Meadows triumph would not be such a shock.
Svetlana Kuznetsova virtually had Wozniacki beat in the last round but choked on some big points, which is a position that Petkovic is unlikely to relinquish if gaining the same advantage.
Wozniacki is perhaps the more gifted all-round player and with the right strategy of keeping Petkovic pegged on the baseline and taking her chances of stepping into the net, she should win.
But, the Dane has only reached the semi finals of one Grand Slam this year and may struggle as the pressure builds.
Wozniacki is the 4/9 favourite in the US Open tennis odds, but German Petkovic is the clear value bet at 7/4.
One of the other quarter finals appears much more clear cut, as Serena Williams can continue her surge through the US Open draw with victory over Anastasia Pavlyuchenkova.
Williams is still to drop a set at the tournament and if Victoria Azarenka and Ana Ivanovic failed in this quest when playing reasonably well, it is unlikely that Pavlyuchenkova will be able to do so, as she has no greater weapons than these players.
It is 1/16 that Williams beats Pavlyuchenkova, but given the way she is serving, 1/5 looks the better bet that she reaches the semi finals in straight sets.
Break point opportunities are likely to be scarce for Pavlyuchenkova, so taking the 4/5 on the match witnessing no more than 18 games could prove profitable as Williams continues her dominant march towards a fourth US Open title.