The US Open can often throw up surprise winners - and this year's Grand Slam finale could be no exception.
With the Olympics taking place just three weeks ago, players are arriving in New York with fewer minutes on a hard court than before, and with more miles in their legs.
"I don't think anyone is coming [to the US Open] in top gear," Christopher Clarey, former New York Times tennis writer, told BBC 5 Live.
"For somebody who is maybe more of a second-tier favourite, this is their year and their opportunity."
Novak Djokovic is the defending champion, but it remains to be seen if the emotional impact of winning a long-awaited Olympic gold on the Paris clay will affect his chances.