She reached her career-high ranking of 42nd in the world on June 6, 2011 and is currently the fifth highest ranked Japanese player in the world at world Number. 153. At Junior level, she reached a career high ranking of Number. 3. Morita is known for strong and consistent two-handed groundstrokes which she hits very flat.
Morita is a small and quick player with excellent footwork and movement around the court.
On September 16, 2008, she beat world Number. 19 Ágnes Szávay in three sets in the Toray Pan Pacific Open.
On January 5, 2009, Morita upset former Wimbledon quarterfinalist Michaëlla Krajicek in the final round of qualifying to reach the main draw of the ASB Classic in Auckland, New Zealand. She faced third set deficits in all three of her qualifying matches, including a 4–1 deficit in her first match against Katie O"Brien.
Her first tournament of 2011 was the 2011 ASB Classic.
She faced Romanian teenager Simona Halep and lost in straight sets despite recovering from being two breaks down in the second set. Her next tournament was the 2011 Moorilla Hobart International. She beat Akgul Amanmuradova.
Ayumi played at the 2011 Australian Open – Women"s Singles where she defeated 27 seed Alexandra Dulgheru in two sets.
She defeated wildcard Caroline Garcia in the second round but lost to Peng Shuai in the third round. At the 2011 Dubai Tennis Championships, Morita qualified by defeating Sophie Lefèvre and Vesna Manasieva.
In the first round of the main draw, she defeated Number. 14 seed Petra Kvitová in two tiebreaks.
Morita beat Indian wildcard Sania Mirza in the second round before losing to Caroline Wozniacki in the third round.
Morita reached the third round of the Australian Open with straight-sets victories over Anna Tatishvili and Annika Beck, then lost to Serena Williams on Rod Laver Arena. Doubles: 2 (0–2)
Singles 16 (8–8)
Doubles 7 (3–4).