Conversation so far:
Did Martina Hingis win?
Martina Hingis won five Grand Slam singles titles, thirteen Grand Slam women's doubles titles, winning a calendar-year doubles Grand Slam in 1998, and seven Grand Slam mixed doubles titles.
How did Martina Hingis do at the US open?
Entering as an unseeded team at the US Open, Martina Hingis and Pennetta reached the final. In the final they lost to Makarova and Vesnina in three sets.
Was there anything special about the US Open when Martina Hingis competed in it?
The 2014 US Open was a tennis tournament played on outdoor hard courts. It was the 134th edition of the US Open.

Question: What day was the US Open?
Self-contained rewrite: What day was the US Open in 2014?