A rain delay saw the match delayed overnight with Cilic two sets to the good but he failed to find his rhythm as the Argentine won 3-6 1-6 6-4 6-4 7-5 to reach the third round of a major for the first time.
German fourth seed Alexander Zverev made the third round, seeing off Taylor Fritz of the United States 6-4, 5-7, 6-7 (0/7), 6-1, 6-2 and faces Latvian qualifier Ernests Gulbis for a spot in the last 16.
But the Croatian collapsed once the match resumed on Court One on Thursday and Pella took full advantage to set up a third round clash with Mackenzie McDonald.
The scoreboard said 6-4 6-3 6-4 to Rafael Nadal but it was an uneasy two-and-a-half hours for the Spanish world number one as he labored past Kazakhstan's Mikhail Kukushkin into the Wimbledon third round on Thursday. It was a very nice surprise to me.
The 11-time French Open champion is looking for his third title at the All England Club and first since 2010.
"I didn't know but I don't see a clock here".
Djokovic hit 15 aces and 31 winners in a commanding win over 33-year-old Zeballos, who was a top 40 player in 2013 but was playing at Wimbledon ranked a lowly 126.
ICE, Trump and Independence Day: Why we're worried this holiday
Just 39 percent of those polled said they approve of the president's policy, while 58 percent said they disapprove. And we have to have immigration laws - and this is on Congress - that reflect our values and our interests.
The world number 133 is in the third round for the first time after winning back-to-back matches on the main tour for only the second time in 2018. Yet hopes that Kyrgios would face another Australian next were dashed after Bernard Tomic lost 2-6, 6-3, 7-6 (7), 7-5 to Kei Nishikori, the 24th seed.
The Kazakh, with a curious undercut double-handed backhand and some clever angles, broke back to level at 3-3 though before Kukushkin wobbled when serving at 4-5.
The 36-year-old American now can not meet a top 32 player until the semi-finals after the scattering of the seeds this week.
Del Potro faces Benoit Paire in the third round after the Frenchman upset 26th-seeded Canadian Denis Shapovalov.
Raonic, if he remains fit, is probably the most likely to meet the 20-time Grand Slam champion at that stage - a match the 2016 runner-up won at the same stage two years ago.
Guido Pella of Argentina took out last year's beaten finalist Marin Cilic of Croatia in the second round at Wimbledon.
For more sports coverage, visit the ABS-CBN Sports website.