Defending champion Novak Djokovic says "it will be the duel of the veterans of the tour" when he faces old rival Stan Wawrinka at Wimbledon on Friday.
Wawrinka, 38, has twice beaten Djokovic in Grand Slam finals but says he "doesn't really stand a chance".
Andy Murray, 36, will finish his second-round match with 24-year-old fifth seed Stefanos Tsitsipas, with the Briton leading by two sets to one.
Carlos Alcaraz, Iga Swiatek, Ons Jabeur and Cameron Norrie are also in action.
One of the highlights of the day could well be the third-round meeting between three-time Grand Slam winner Wawrinka against 36-year-old Djokovic, who clinched his 23rd major at the French Open last month.
Two of Wawrinka's Slams have come against Djokovic - the 2015 French Open final and the 2016 US Open final - and the Serb has not forgotten.
Asked what role 88th-ranked Wawrinka has played in his career, a laughing Djokovic, 36, said: "Well, he took away two Grand Slams from me.
"No, I like Stan a lot. He's a great person and really inspirational what he's doing at his age. He's almost 40 and he still keeps going strong, that's something not many people can do.
"We can't forget he's a three-time Grand Slam champion, Davis Cup winner and also Olympic gold. He's had a fantastic career.
"We haven't faced in quite some time. It will be the duel of the veterans of the tour."
Wawrinka, who has suffered with numerous injuries and needed knee surgeries since his Grand Slam successes, says he will relish the match with Djokovic, although expects his tournament to end before the weekend.
"There's zero opportunity to win Wimbledon for me," said Wawrinka.
"It's an honour to play Novak here, I was missing that in my career - to play him in the Grand Slam in Wimbledon.
"Hopefully I can make a competitive match, but if you look at recent results, I don't really stand a chance."
First on Centre Court at 13:30 BST is men's top seed Alcaraz and he warmed up for his second-round match against French world number 84 Alexandre Muller with an hour-long practice session with British number one Norrie.
The conclusion of the Murray v Tsitsipas match, in which the Briton leads 6-7 (3-7) 7-6 (7-2) 6-4, will follow Alcaraz and Muller, not before 15:00.
Women's number one Swiatek comes after Murray. The Polish four-time Grand Slam winner, who has only dropped six games in the opening two rounds, is in third-round action against 30th seed Petra Martic of Croatia.
All the matches on Court One are in the second round with the schedule backed up because of rain earlier this week. Women's second seed Aryna Sabalenka opens proceedings at 13:00 against Varvara Gracheva of France, before Norrie plays American Christopher Eubanks of the United States with Jabeur against China's Bai Zhuoxuan third on.
Britain's Liam Broady, a winner against fourth seed Casper Ruud on Thursday, will be looking to reach the last 16 of a Grand Slam for the first time when he faces 26th seed Denis Shapovalov of Canada on court two.
Elsewhere, Daniil Medvedev, the Russian third seed, needs only two games for victory against France's Adrian Mannarino. Medvedev led 6-3 6-3 4-4 when bad light ended play on court two on Thursday evening.
There are a host of matches in the men's, women's and mixed doubles.
Among those in action are Britain's Joe Salisbury and American Rajeev Ram, the men's third seeds, all-British pairing Harriet Dart and Heather Watson and the duo of Britain's Neal Skupski and American Desirae Krawczyk, the second seeds in the mixed doubles.