Djokovic, 38, overcame illness to win his first-round match in four sets but breezed through rounds two and three.
Saturday’s masterful victory over fellow Serb Miomir Kecmanovic was his 100th match win at Wimbledon. He is the third player to reach that landmark, following Martina Navratilova (120) and Federer (105).
Sinner, 23, has found things even more comfortable so far, winning his first three matches without dropping a set and spending less than five and a half hours on court.
But both title contenders will come up against a seeded player for the first time in this tournament on Monday.
Djokovic is first on Centre Court against world number 11 Alex de Minaur of Australia (13:30 BST), with Sinner rounding things off on Centre against Bulgaria’s former Wimbledon semi-finalist Grigor Dimitrov.
Sandwiched in between is Andreeva’s fourth-round match against American 10th seed Emma Navarro, who ended Barbora Krejcikova’s title defence on Saturday.