Compatriot Joe Salisbury is also through to round three with his partner Frederik Nielsen after their opponents Rohan Bopanna and Edouard Roger-Vasselin retired two sets and 3-2 down in the third. "I am a little surprised that I won, I was a little bit lucky today".
Just like in the opening two matches, Roger was the dominant figure on the court, never facing a break point and keeping the pressure on Jan-Lennard with 14 break points he created, converting four to stay in front from start to finish.
Having made 18 unforced errors in each of the first two sets, Giorgi tightened up her game to make just eight in the third and advance to the last 16 at Wimbledon for the first time since 2012.
Del Potro faces Benoit Paire in the third round after the Frenchman upset 26th-seeded Canadian Denis Shapovalov.
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.
Cape Town - Kevin Anderson will be confident heading into Friday's Wimbledon third round encounter against German veteran Philipp Kohlschreiber.
"Stopping last night was not a nice feeling to go to bed with", said Zverev. Happy for the victory and happy with way I played.
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.
Unseeded American Taylor Fritz also unexpectedly took a 2-1 lead over world No. 4 and tournament fourth seed Alexander Zverev before their second round match suspended by darkness.
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).
Ken Skupski was back in action later in the day, alongside fellow Brit Anna Smith, to make it through to the mixed doubles second round with a 6-1 6-7 (3-7) 7-5 victory over Nicholas Monroe and Oksana Kalashnikova.
Keys, who has only reached one quarter-final at Wimbledon despite a powerful game, said she had made the mistake of allowing herself to think about a possible fourth-round clash with seven-times champion Serena Williams.