Pliskova is now the only top-10 women's seed through to the second week, with eight others eliminated, and world No.1 Simona Halep looking to join her when she plays Taiwan's Su-Wei Hsieh on Saturday.
The 38-year-old American, last year's runner-up, was the oldest women's singles entrant in 2018.
But Rodina, 29, held her nerve to reach the last 16 at a grand slam for the first time.
Keys' departure comes hot on the heels of early exits for two-time Wimbledon victor Petra Kvitova, 2004 All England Club champion Maria Sharapova, world number two Caroline Wozniacki and US Open title holder Sloane Stephens.
Rodina won nine games in a row to move a set and two breaks ahead before Keys recovered from 4-0 down in the second set to set up a decider.
The world number 64 has had to fight back from two sets to love down in his first two matches to beat Leonardo Mayer and 39-year-old Ivo Karlovic.
Survivors of fatal Bahamas boat explosion speak out for the first time
It shows people jumping "into the shallow water in an attempt to rescue passengers in the burning boat", according to ABC News . A fiery explosion on a small tour boat in the Bahamas killed one person and injured nine others on Saturday, authorities said.
Williams is the only past Wimbledon champion remaining in the field.
The 36-year-old Swiss has won 26 consecutive sets at the All England Club.
"I'm happy to be through".
The defending champion made light work of his first two opponents in SW19 and it was a familiar story today as he clinched a 6-3 7-5 6-2 win.
The South African eighth seed reached the third round when he completed a four-set victory over Italy's Andreas Seppi on Thursday. "I am having a good season - made the quarters at the French Open - it's all coming together".
Ninth seed John Isner saved two match points and served 64 aces to overcome Belgian Ruben Bemelmans 6-1 6-4 6-7 (6-8) 6-7 (3-7) 7-5 in three hours 46 minutes to reach the third round.