Pella, a clay-court specialist who until Thursday had never reached the third round of a Grand Slam and until this week had yet to win a match here, claimed the biggest scalp of the day as the 28 year-old overturned a two-set deficit in breath-taking fashion, finally converting a fourth match point in the fifth.
"Of course, I am surprised a little bit", Rodina said afterward, "because I won".
Switzerland's Roger Federer gives a thumbs up after winning his men's singles match against Germany's Jan-Lennard Struff.
The Israeli tennis star Dudi Sela was beaten Tuesday by world number one Rafael Nadal in the first round of the Wimbledon Grand Slam tournament, in his third loss to the Spaniard in three career matches.
Defending champion and top seed Federer, by contrast, has made the third round without breaking sweat.
But instead the 38-year-old was worn down by Dutch 20th seed Bertens in a dramatic third round clash lasting two hours and 40 minutes in sweltering heat on Court One.
Rodina, a 120th-ranked Russian qualifier, upset Keys 7-5, 5-7, 6-4.
"Stopping last night was not a nice feeling to go to bed with", said Zverev.
"I'm happy I found a way today".
"I worked really, really hard (to get back playing) and it's been a long, arduous road but I always expected to come out and do the best I can do".
Russia's Ekaterina Makarova defied second round victim Wozniacki's churlish prediction that she wouldn't progress further in the tournament by reaching the last 16.
Monfils made it through to the fourth round for the first time after beating Sam Querrey.
Darkness descended at just the right time as the German came back to win 6-4 5-7 6-7 (0/7) 6-1 6-2, justifying his eventual decision to not withdraw.
Anderson earlier became the first man through to the fourth round after beating Philipp Kohlschreiber 6-3 7-5 7-5.
Venus couldn't complete a third consecutive comeback as she lost to 20th-seeded Kiki Bertens of the Netherlands 6-2, 6-7 (5), 8-6 in the third round on Friday (Saturday NZT).
South African eighth seed Kevin Anderson and Frenchman Gael Monfils also reached the final 16 on Friday.