Serena Williams is a six-time champion at Flushing Meadows.
Serena has made history yet again by winning her opening match against fellow American Kristie Ahn.
Serena suffered a number of surprise defeats in the lead-up to the tournament.
The 23 time Grand Slam title winner was tested against the 96th ranked Ahn.
In the process, the 38-year-old surpassed Chris Evert as the all-time leader in matches won at the US Open.