Andreeva announced herself by claiming this year's French Open title on clay, but she has shown she is no slouch on hard courts.
The 19-year-old, who looked right at home during her run to the mixed doubles semi-finals with fellow Russian Andrey Rublev last week, relied on her power and precision again to dispatch Tjen under the roof of Louis Armstrong Stadium.
"Our match in Cincinnati was really tough... the conditions were tough as it was hot and humid," Andreeva said, referring to her win over Tjen in the US Open tune-up last month.
"It was the first time I was playing her... She's not easy to play against. Today, I was just trying to talk to my coach to see what we can do better in order for me to feel confident on the court. I was trying to be very aggressive.
"I was trying to go for my shots, and after everything, I just feel like today it was a better match."
Andreeva drew first blood with a fiery forehand winner to break for a 3-2 lead in the opening set, which the fifth seed completely dominated thereafter and closed out after only 31 minutes of action.
There was no respite for Tjen in the second set as Andreeva dialled up the intensity to claim another early break before she sealed the victory to set up a clash with Germany's Eva Lys in the next round.