Andy Murray says he's playing the best tennis of his career as he looks to capitalize on the growing frailties of his rivals and capture a second US Open title.

Ahead of Monday's start to the season's final Grand Slam, the 29-year-old is the sport's man of the moment.

Since losing the French Open final to Novak Djokovic in June, Murray has won the Queen's Club, a second Wimbledon title and successfully defended his Olympic singles crown in Rio.

His career-best 22-match win streak was ended by Marin Cilic in the final at Cincinnati last week when he simply ran out of gas.

But that hasn't dented Murray's confidence that he can claim a second US Open, four years after his breakthrough in New York saw him become the first British male in 76 years to win a Grand Slam.

The three-time major winner said he is taking positives from being in the twilight of his career.

"You have to make the most of every opportunity. It's a slightly different mentality to maybe when you're younger and you feel like you have a bit more time on your side," he said.

Murray has played in the finals of the first three majors of 2016, losing to world No 1 Djokovic in Melbourne and Paris before defeating Canada's Milos Raonic in straight sets at Wimbledon.

The only worry for Murray is his relatively mediocre recent record in New York - runs to the quarterfinals in 2013 and 2014 were followed by a fourth-round exit to Kevin Anderson 12 months ago.

Murray starts his campaign against fiery Lukas Rosol. The last time they met in Munich in 2015, Murray described the feisty Czech as the "most-hated man" in the sport.

The Scot's consistency on the tour in recent weeks is in stark contrast to the rollercoaster fortunes of Djokovic, the defending US Open champion.

After he won his first French Open to complete a career grand slam, all talk was of the Serb going on to defend his Wimbledon and US Open titles and clinch a calendar slam.

That's a feat so rare that only two men have ever achieved it, with Rod Laver the most recent in 1969.

The expectations proved too heavy a burden when the 12-time major winner was dumped out of Wimbledon in the third round for his earliest loss at a major in seven years.

Although he then won a record 30th Masters trophy in Toronto, a stunning first-round loss to Juan Martin del Potro at the Olympics and a withdrawal from Cincinnati with a wrist injury suggested all is not well with the 2011 and 2015 US Open winner.

"I am not 100 percent. Hopefully on Monday, when it all starts, I will be there," said Djokovic, who faces big-serving Jerzy Janowicz of Poland in his opener.

"The wrist has not been ideal for three weeks. There are different methods of healing. One involved electrical therapy to enhance my recovery process."

Outside of the top two, five-time champion Roger Federer, who has played every US Open since 2000, called time on his season after a five-set semi-final loss to Raonic at Wimbledon. The 35-year-old Swiss aggravated a knee injury in that defeat.