It was an unconvincing display from the Russian against a relative unknown in 18-year-old Kenin, but she managed to get herself over the line with a 7-5, 6-2 win.
Sharapova, who won this competition back in 2006, was far from her best – hitting 25 unforced errors in the opening set.
However, her opponent – despite putting in a dogged display to make it 5-5 in a opening set that lasted 67 minutes – largely let Sharapova off the hook as he struggled to hold her serve.
The second set proved to be more plain-sailing for the former world No. 1 as he cruised into a 3-0 lead.
Kenin did reduce the deficit due to Sharapova’s double fault in the fourth game, which gifted her a route back into the match.
But her joy was short lived as Sharapova was again let off the hook by her opponent and got the job done.
Prior to this victory, the five-time Grand Slam champion beat Simona Halep and Timea Babos.
But in order to reach the quarter-finals at Flushing Meadows she must beat 16th-seed Anastasija Sevastova.