Mirra Andreeva, 17, is the youngest WTA champion since Coco Gauff won 2021 Parma.
One Magdalena stood supremen in the first WTA all-Polish final.
"I'm sure Rafa will be in tomorrow's doubles because he trained well today," Spanish captain David Ferrer said.
The American started with Witt about a week and a half ago.
The Poles pushed past a pair of Czechs on Thursday in Prague.
"I'm happy I get to do this one more time," Andy Murray said of his Olympic farewell.
World No. 4 pulls out of Paris.
