London: Novak Djokovic and Roger Federer can take a step closer to a Wimbledon semi-final duel when they battle for places in the last-16 on Friday.
Defending champion and top seed Djokovic, bidding for a third successive Wimbledon title and fourth in total, takes on America's Sam Querrey.
Victory will give the Serb a 31st successive Grand Slam win taking him level with Rod Laver on the all-time list, six behind the record set by Don Budge in 1938.
Djokovic has an 8-1 career record over the 28-year-old Querrey who has only reached the fourth round on one occasion, back in 2010.
Third seed Federer, the seven-time champion, saw off world number 772 Marcus Willis in the second round and Friday faces another British player, 91st-ranked Daniel Evans.
Federer is looking to clinch his 150th win on grass courts.
Evans, 28, hopes to become the first British man other than Andy Murray to reach the round of 16 at a Grand Slam since Tim Henman made the semi-finals at the 2004 US Open.
"It's not a day out for me. It's a good opportunity. I'm taking it seriously," Evans said.
"He's not a normal guy obviously. It would be stupid to say it's not a special occasion to play him."
Centre Court action gets underway with Swiss fourth seed Stan Wawrinka taking on former US Open champion Juan Martin del Potro who is steadily rebuilding his career after a series of wrist injuries pushed him to the verge of quitting.
Wawrinka is a former French and Australian Open champion.
The last time two Grand Slam champions met in the second round at Wimbledon was in 2008, when Marat Safin defeated Djokovic.
Del Potro last played on Centre Court in 2013 when he lost an epic semi-final to Djokovic.
Defending women's champion Serena Williams, chasing a seventh Wimbledon title and Open era record-equalling 22nd major, faces fellow American Christina McHale on Centre Court.
Williams has a 2-0 head-to-head advantage over McHale, the world number 65, with both wins coming in 2016.
Sister Venus, a five-time champion and the oldest woman in the draw at 36, is on Court One facing Russia's Darya Kasatkina.
That comes a day after Williams was exiled to Court 18, a decision which led to the American to call for more equality when it came to scheduling.
Also bidding for third round spots on Friday are Australian 15th seed Nick Kyrgios who faces Dustin Brown of Germany in a clash between two men who have both defeated Rafael Nadal at Wimbledon in recent years.
Japanese fifth seed Kei Nishikori meets Russia's Andrey Kuznetsov while two-time women's champion Petra Kvitova takes on Ekaterina Makarova of Russia.