The eyes of the tennis world will be transfixed on New York City for the next two weeks when the best male and female players on the planet compete to win the 2019 US Open.
Ahead of the start of the final grand slam of the season, here is a look at the biggest talking points from Flushing Meadows.
Djokovic aims to go back-to-back
Novak Djokovic's recent grand slam record is nothing short of remarkable. The world No 1 has won four of the past five major titles, with only Rafael Nadal's predictable success at the French Open leaving a gap on the CV.
To make it five grand slam titles in six tournaments, Djokovic will have to achieve something that has not been done since Roger Federer won his fifth successive trophy in 2008: defend the US Open title.
Based on his limited preparations - Djokovic lost in the Cincinnati Masters semi-final to Daniil Medvedev in his only warm-up event - and his tough-looking draw - a rematch with Medvedev and meetings with Federer and Rafael Nadal are likely - the top-seeded Serbian faces a tough task.
But this is Novak Djokovic, a ruthless, unwavering champion who more often than not finds a way to win on the grandest stages. His Wimbledon final triumph over Federer is a case in point: Djokovic won 14 less points and four fewer games, but still emerged with the trophy.
Recent history may not be on Djokovic's side, but he has made a habit of rewriting history throughout his career, and there will be few surprises if he wins major title No 17 to take a step closer to another significant milestone: Federer's all time grand slam record of 20.
Medvedev the 'Big Three' gatecrasher?
Many have tried and failed, but the "Big Three" of Djokovic, Nadal and Federer remains the pre-eminent force in men's tennis, particularly at the four majors.
Daniil Medvedev has positioned himself at the head of the challengers' queue for the US Open following a superb run of form during the US Open series - the handful of events that lead up to the grand slam.
Medvedev played in three of those tournaments - two of which were Masters 1000 events - and reached the final in every one of them.
After falling short at the Washington Open to Nick Kyrgios and the Rogers Cup to Nadal, it was third time lucky for the Russian at the Cincinnati Masters.
It was not just his sustained brilliance or title victory that caught the attention but his win over Djokovic last week. He has now beaten the world No 1 in their past two meetings this year.
As impressive as Medvedev has been this season (no ATP Tour player can top his 44 match wins), he will be judged on his grand slam record.
Can he mark himself out as the leader of the next generation by winning the US Open?
The world No 5 is on course for a quarter-final showdown with Djokovic. Pass the ultimate test and he will install himself as a genuine contender to win the title.
Williams goes again
Serena Williams has been 'stuck' on 23 grand slam singles titles for what seems an eternity. One more trophy will pull the American level with Margaret Court's long-standing record.
Of course, there are key circumstances as to why Williams has not added a major trophy to her collection since the 2017 Australian Open, becoming a mother chief among them.
However, since her return, Williams has had three chances to get over the line and stumbled each time. Twice in Wimbledon finals, Williams has been thoroughly outplayed - first by Angelique Kerber last year and then by Simona Halep in July.
But while losing to two former world No 1s with grand slam-winning pedigree was no great shock, the defeat 12 months ago to first-time finalist Naomi Osaka - and the manner in which the final descended into chaos - would have stung Williams a whole lot more.
Williams, who was penalised a game during the 2018 final after aiming a volley of verbal abuse at the chair umpire after being warned for illegal coaching, now has a chance to redeem herself, but she faces similar obstacles as other recent grand slam campaigns.
Limited competitive action and fitness concerns - Williams has played just seven tournaments this season, withdrawing injured in three - mean once again her preparations have been far from ideal.
It has been this lack of preparation that has seen Williams run out of steam and fall at the last hurdle in her last few grand slams, and she will need to find another level from somewhere if she is to get that elusive 24th title.
But if there is one player who can triumph in such adversity, it's Serena Williams.
