American great Serena Williams' impending farewell to the court will understandably grab most of the attention when an intriguing US Open packed with storylines begins on Monday.

Spain's Rafael Nadal has only played once since pulling out of Wimbledon through injury but has the chance to extend his men's singles record of 22 major titles with nearest rival Novak Djokovic not allowed to play.

The 35-year-old Serb, who is one major title adrift, is unvaccinated against Covid-19 and is not allowed to enter the United States as a result.

Going into the final Grand Slam tournament of the year, BBC Sport runs through the major talking points in New York.

How long will Serena's farewell last?

Only one place to start: the end of Serena Williams as a tennis player.

The 23-time Grand Slam champion, who turns 41 next month, says she is "evolving" away from playing tennis and this will be the final tournament of her glittering career.

While reticent to use the word 'retirement' that is what the American is planning to do. It means there is set to be an emotional farewell on Arthur Ashe Stadium when the six-time singles champion walks off for what she anticipates will be the final time.

But when will that be? A deep run in the singles looks unlikely and finally landing that record-equalling 24th major title would almost be a shock of Raducanu proportions.

Williams is also playing in the women's doubles alongside older sister Venus after they received a wildcard.

Williams has only played five singles matches this year, including a first-round thrashing by Raducanu in Cincinnati two weeks ago, and faces Montenegro's world number 80 Danka Kovinic in Monday's night session on Ashe (00:00 BST, Tuesday).

A knee injury had hampered her preparation for the Cincinnati tournament and pushed the first-round match against the Briton back to Tuesday after initially being scheduled for Monday.

Williams did appear to be moving better in her practices at Flushing Meadows this week, but it will interesting to see what level she is at when she faces Kovinic.

What shape is defending champion Raducanu in?

This time last year, Raducanu was an 18-year-old novice preparing for her first overseas Grand Slam appearance after battling through qualifying.

Now a household name after her stunning victory in New York, scrutiny has been sharp as the world watches her development with intrigue.

Understandably, it has been a testing transfer onto the WTA Tour for the youngster, whose pre-season preparation was ruined by catching Covid and hampered since by niggling injuries.

But, as we saw in Cincinnati, the quick US hard-courts seem to bring the best out of the world number 11.

Raducanu backed up the victory against Williams with another stunning win against Victoria Azarenka, also a former world number one, and both performances were reminiscent of the confident, clinical style which led her to victory in New York.

There was a reality check in the next round, however, when she played well but could not outplay American world number eight Jessica Pegula.

More concerns about her fitness came at Flushing Meadows on Friday, although she insisted a wrist problem was not serious.

Raducanu, who starts on Tuesday with a tough draw against France's Alize Cornet, looked in much better shape when she practised against Wimbledon champion Elena Rybakina on Saturday.

What about the other Brits?

By ranking and form, it is seventh seed Cameron Norrie who leads the British hopes.

The 26-year-year-old left-hander made his breakthrough at a major with a run to the Wimbledon semi-finals and has continued his good form by reaching the Los Cabos final and Cincinnati semi-finals.

Norrie has moved into the top eight seeds at Flushing Meadows, which means he cannot face a higher-ranked opponent until the quarter-finals should he get there.

Former world number one Andy Murray is outside of the seeds after winning three of his seven matches since arriving in North America to build up for the major he won in thrilling style in 2012.

Dan Evans is seeded at a career-high 20th as he looks to better last year's run to the fourth round, while 20-year-old Jack Draper makes his debut in the main draw of an overseas major after moving to the verge of the world's top 50.

Former British number one Kyle Edmund is playing his first major singles event for almost two years having been out with a knee injury, while 26-year-old Harriet Dart has direct entry into the draw for the first time after cracking the world's top 100 this year.

World number one Joe Salisbury and his American partner Rajeev Ram are the top seeds in the men's doubles as they look to defend their title, while Neal Skupski - who has won six titles this year alongside Dutchman Wesley Koolhof and ranked third in the world - is also among the favourites.

In the wheelchair events, Alfie Hewett and Gordon Reid will team up in their bid for a sixth successive US Open doubles crown, as well as competing in the singles. Lucy Shuker competes in both women's events, while two-time US Open quad singles and four-time quad doubles champion Andy Lapthorne will go for more success.

Who are the other women's contenders?

World number one Iga Swiatek remains the standout player of the season, although her dominance has faded since her 37-match winning streak was ended at Wimbledon.

Swiatek, 21, has won four of her past eight matches and, with success on hard courts earlier this year, is still considered the favourite.

The major home hope is Coco Gauff. The 18-year-old American reached her first major final when she lost to Swiatek at Roland Garros and her form on the American hard courts - quarter-final appearances in San Jose and Toronto - have been encouraging.

Gauff's doubles partner Pegula, 28, is also one of the in-form singles players on the WTA Tour. After reaching two major quarter-finals this season - plus the Madrid final, along with Miami and Toronto semi-finals - she will fancy her chances of a deep run in her home major.

Two-time Grand Slam champion Simona Halep won the Toronto title earlier this month and is back into the world's top 10, while France's Cincinnati champion Caroline Garcia and Brazil's Beatriz Haddad Maia - who lost to Halep in the Canadian Open final - come in on hot streaks.

Greek third seed Maria Sakkari will be hoping to go further after reaching the semi-finals last year, while Wimbledon champion Elena Rybakina is seeded 25th because ranking points were not awarded at the All England Club.

Can Nadal capitalise on Djokovic's absence?

Djokovic moved to within one major title of Nadal by winning Wimbledon for a sixth time, but misses the opportunity to level with the Spaniard in New York.

Nadal, 36, says it is "very sad news" that his rival cannot play, even though it strengthens his hopes of a fifth US Open win.

The second seed has only played once since pulling out of Wimbledon with an abdominal injury, losing to Croatia's Borna Coric in Cincinnati, but says he is playing at a "high level of intensity" in practice.

"I am doing things the best way that I can. I hope to be ready for the action," said Nadal, who plays Australia's Rinky Hijikata in Tuesday's night session on Ashe.

"That's the only thing that I can say. With the tools that I have today, I hope to be competitive enough to give myself a chance."

What about the other men?

Djokovic's absence, Nadal's disrupted preparations and a lack of recent dominance by others means the men's draw is pretty open.

Defending champion Daniil Medvedev is the top seed and, while he usually thrives on the North American hard courts, the 26-year-old has not yet hit his peak in a mixed bag of form.

After missing Wimbledon because Russian players were banned, Medvedev returned to win a title in Los Cabos, suffered an early exit in Montreal and was beaten in the Cincinnati semi-finals by Greece's Stefanos Tsitsipas.

The draw sees a potential tough fourth-round meeting with Australia's Nick Kyrgios, who has been one of the in-form players in recent months and was responsible for Medvedev's loss in Montreal.

This season Kyrgios has appeared more tuned in to what he must do to be successful and fulfil his undoubted potential.

That enabled the 27-year-old to reach his first Grand Slam final at Wimbledon and he continued his hot form by winning the Washington title.

Spanish third seed Carlos Alcaraz, who reached the quarter-finals last year, is one of the favourites after a stunning year where the 19-year-old has broken into the world's top five.

Several of the other leading seeds - including Tsitsipas, Norway's Casper Ruud, American Taylor Fritz and Spain's Pablo Carreno Busta - could come into the equation after decent runs recently.