Guernsey teenager Watson qualified automatically for the main draw only two years after winning the junior title at Flushing Meadows thanks to a swift rise up the rankings.
The 19-year-old, ranked 104th in the world, was guaranteed a high-profile debut when the draw was made and she will play on the biggest court in tennis, Arthur Ashe Stadium - providing the first two matches do not overrun.
Sharapova already has first-hand experience of what the new generation of British players can do after being pushed by 17-year-old Laura Robson in the second round at Wimbledon in June, and she will certainly not be underestimating Watson.
The Russian said: "I've never played her before. I saw a little bit of her matches in the past, I think at Wimbledon, her first rounds.
"She's someone that's up and coming, and those are sometimes dangerous because they're quite fearless when they go on the court, they don't have much to lose.
"It's not too often that you play an opponent you haven't played against before, so it's not an easy first round."
Sharapova went on to reach the final at Wimbledon, eventually losing to Petra Kvitova, and she continued her good form in Cincinnati earlier this month, beating Svetlana Kuznetsova, Samantha Stosur, Vera Zvonareva and Jelena Jankovic to lift the title.
The third seed said: "I came into Cincinnati asking to play a lot of matches for myself, as many as I could at that tournament. It was great to win the tournament. I beat some really good opponents, played some good matches.
"The final was a little wacky but I just managed to win that one. Obviously coming into the Open it's great to have a title under your belt."
This year Sharapova has returned to something like the form that brought her three grand slams by the age of 20 before shoulder problems set her back.
Prior to Wimbledon, she reached her first French Open semi-final for four years, and the 24-year-old has no problem bearing the weight of expectation.
Sharapova said: "I have been seeded a lot lower and I've still been one of the favourites, so it's not anything new for me that people expect me to do well.
"I just feel like this year I've improved. Last year I felt like I would play a couple of good matches and then I'd play a bad match. I didn't have that sense of consistency, and that's something I feel has changed this year."
Sharapova is a clear second favourite to lift the title behind a resurgent Serena Williams, and there is guaranteed to be a different winner for the first time in three years after Kim Clijsters was forced to withdraw with a stomach muscle problem.
Sharapova had a lot of sympathy for the Belgian, and said: "It's obviously unfortunate that she can't come back as a defending champion.
"I have been in that position before. It's definitely tough, there is no doubt about it, to not be able to defend such a big title. But it's sometimes the adversity that we're faced with."
The Russian, meanwhile, backed Kvitova to return to top form at Flushing Meadows. Having collected four titles this season, culminating with her stunning Wimbledon victory, the Czech has managed only two victories since.
Sharapova added: "It's not easy, that's for sure, especially after your first one, definitely. I think she's a good enough player to find her form back here."
Kvitova will open proceedings on Arthur Ashe against Romania's Alexandra Dulgheru while second seed and last year's beaten finalist Vera Zvonareva, eighth seed Marion Bartoli and ninth seed Samantha Stosur are also in action."