Pegula, seeded third, never trailed in a contest where she won 80% of her first serve points and broke Tig's serve six times.
Pegula edged Svitolina in a three-set battle in Washington D.C. earlier this month and holds a 3-1 advantage in their career meetings.
"Every single match we play is just a really good battle," Pegula said.
Svitolina returned in April following the birth of her daughter and Pegula said she had already got back to top form.
But she settled in from there, breaking Kenin for 3-3 and again to level the contest at a set apiece.
Persons:
Jessica Pegula, Romania's Patricia Maria Tig, Mike Segar, Patricia Maria Tig, Elina Svitolina, Tig's, Anastasia Pavlyuchenkova of, Pegula, Svitolina, Arthur Ashe, Carlos Alcaraz, Ashe, Carlos, It's, Daria Kasatkina, American Sofia Kenin, Kenin, Rory Carroll, Peter Rutherford
Organizations:
Tennis, U.S, Buffalo, Washington D.C, American Sofia, Thomson
Locations:
Flushing Meadows , New York, United States, Romania, Ukrainian, Anastasia Pavlyuchenkova of Russia, Washington, American, Los Angeles