(AFP) - A gleaming new retractable roof is the crown jewel in a US$600 million (S$811.6 million) US Open makeover that bets big on tennis as the sport enters a transition period.

Anticipation for the final Grand Slam tennis tournament of 2016 has been mounting, in part because it will mark the premiere of a sweeping transformation of the US Open's home, the Billie Jean King National Tennis Centre in Queens.

The centrepiece of the upgrade is the moveable roof over Arthur Ashe Stadium, the facility's mammoth centre court, ensuring continuous play, including for the final weekend's championship matches.

Other major modifications include the launch of a new 8,000-seat Grandstand court and the relocation of almost all of the tournament's outside courts, a shift that allows more walkways and retail space.

A 50 per cent increase in the number of Wifi access points will provide better connectivity for smartphone-addicted patrons across the 40-acre site.

The upgrade comes as tennis begins to eye a future without a group of elite players who have defined the sport in the twenty-first century.

The 2016 tournament, which starts on Monday, will be the first of the millennium without the injured Roger Federer of Switzerland.

Questions also surround the fitness of women's No. 1, Serena Williams of the US, who was hobbled by a shoulder injury during a third-round loss at the Rio Games.

The era's other major champions are 30 or approaching it, including Serbia's Novak Djokovic, Spain's Rafael Nadal, Britain's Andy Murray and Russia's Maria Sharapova, who is suspended for doping.

"We are transitioning from what many have described as a sort of 'golden era'," said Lew Sherr, chief revenue officer for the United States Tennis Association.

"We will be in the not-too-distant future be transitioning to a new crop of hopefully great, exciting new players."

Organisers also hope to increase mentions on social media with the increase in Wifi access points, which can improve leverage with sponsors and broadcasters.

The US Open is "very lively, very loud, very advertising-rich and there's a lot of brands all over the place," said John Kent, a worldwide sponsorship executive at IBM who works on all four tennis Grand Slams.