Maria Sharapova expects a tough battle against Heather Watson when the pair clash in the opening round of the US Open on Sunday. 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.