Nadal skipped the Cincinnati Masters after winning the Rogers Cup to ensure he was fully fit ahead of the final Grand Slam of the year.
The world No 1 enters the tournament as the second favourite, behind Novak Djokovic, but he is still expecting to win the 18th Grand Slam of his career.
Roger Federer is also looking to end the season on a high after failing to defend his Wimbledon crown last month.
But Nadal has warned his rivals that he will have the momentum because of his recent form – and he is going to take no prisoners along the way.
“That’s important for the feelings, the confidence,” Nadal said.
“I am here just trying to improve every day.
“Of course, it is important what happened before a Grand Slam. If you are playing well before, is easier to play well in a Grand Slam.
“At the same time, it’s true that especially a few players are able to increase the level of concentration, the level of tennis, level of intensity in some places.
“If you have to do it, this is one of the places.”
Nadal is also looking forward to playing in front of the New York supporters once again.
“Being honest, I always had a great connection with the crowd here,” he added.
“The crowd brings me to another level of energy.
“That’s something that I enjoy.”
Rafael Nadal US Open draw: What is his projected route to the final?
First round: D Ferrer
Second round: V Pospisil or L Lacko
Third round: K Khachanov
Round of 16: K Edmund
Quarter-final: K Anderson
Semi-final: JM del Potro
Final: R Federer