World number one Alcaraz tackles 84th-ranked Alexandre Muller of France, who is making his Wimbledon debut.
Alcaraz, playing just his fourth grass-court event, has had to wait until Friday to get his second round under way due to the torrential rain which wreaked havoc earlier in the week.
"Every day you learn something new on grass," said 20-year-old Alcaraz.
"Every time that I get out on to the court playing, it's better for me. I get more experience that is really, really important on this surface."
By contrast, world number two Djokovic, who is bidding for a record-equalling eighth Wimbledon and 24th Grand Slam title, had his second-round obligations wrapped up by Wednesday.
The 36-year-old faces three-time major winner Stan Wawrinka, two years older than the Serb, for a place in the last 16.
"It's the duel of the veterans," said Djokovic.
The two have met 26 times over their 17-year rivalry.
Wawrinka has won just six of those but crucially two were in Grand Slam finals, at the 2015 French Open and the US Open, 12 months later.
Friday's match will be the first time they have played on grass.
"I will enjoy it if I don't get killed," joked the Swiss.
Two-time champion Murray was within touching distance of the third round on Thursday evening when his clash against fifth-ranked Tsitsipas was halted due to local curfew regulations.
Murray lost the first set but roared back to lead 6-7 (3/7), 7-6 (7/2), 6-4.
The players will resume on Centre Court once Alcaraz and Muller have completed their match.
Thursday's suspension came at the right moment for Murray, who fell and appeared to hurt his groin, leaving him screaming in pain as he served for the third set.
However, the world number 40 picked himself up to serve it out.
Serbia's Laslo Djere awaits the winner.
In early action on Friday, two-time champion Petra Kvitova eased past Aliaksandra Sasnovich 6-2, 6-2, avenging her defeat to the Belarusian in the first round in 2018.
Ukraine's Marta Kostyuk made the last 32 for the first time when Paula Badosa suffered a recurrence of a back injury and quit their second-round match.
- Badosa quits -
Kostyuk was 6-2, 1-0 ahead when her Spanish rival retired after just 36 minutes on Court 18.
Badosa immediately pulled out of the mixed doubles she was due to play with boyfriend Tsitsipas.
"My back's got worse. I need to take some days off. I wanted to try in the match today but the smartest thing was to stop," said Badosa, who also missed the Australian Open and French Open this year because of injury.
The 21-year-old Kostyuk next faces Madison Keys of the United States, a quarter-finalist in 2015.
Women's world number one Iga Swiatek, the reigning US Open and French Open champion, eyes the last 16 when she faces experienced Petra Martic of Croatia.
Swiatek has dropped just six games in two rounds.
Men's third seed Daniil Medvedev returned to complete his second-round clash against Adrian Mannarino, the Frenchman who defeated him at Wimbledon five years ago as well as on grass at 's-Hertogenbosch last month.
The mercurial Russian was two sets and 4-4 ahead when play was halted on day four but quickly wrapped up the tie in the tie-break.
"He can be up and down. When he's up, he's like top five," said Medvedev, who was banned last year because of Russia's invasion of Ukraine.
Women's second-ranked Aryna Sabalenka was also banished along with all other Belarusians due to her country's support of Moscow.
The Australian Open champion has racked up 35 match wins in 2023 -- second only to Swiatek's 40.
Sabalenka, a semi-finalist at Wimbledon on her last appearance in 2021, tackles Varvara Gracheva, who recently switched from Russian to French nationality.
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