A year ago, Federer became the first man since Bjorn Borg in 1976 to win the title without dropping a set. In the women's draw it is being generated by a mix of old and young aspirants after the filleting of the top 10 which left only seventh seed Karolina Pliskova upright after six days.
Pella delivered the biggest upset so far in the men's draw when he eliminated third-seeded Marin Cilic in a match that was carried over to Thursday. Martina Navratilova shares Federer's 89 per cent win rate, but Navratilova has quite a few more matches up her sleeve.
The resurgent Novak Djokovic, who reached the Queen's Club final last month, knocked out British No 1 Kyle Edmund to underline his grass-court credentials.
But after hoisting the French Open trophy for a record 11th time less than four weeks ago, Nadal seems energized at the prospect of completing the Roland Garros-Wimbledon double for the third time in his career.
Although Federer is approaching peak form, he knows world number one Rafael Nadal - yet to drop a set in his first three matches - and three-time Wimbledon victor Novak Djokovic - playing his way back to his best this week - are lurking as potential final opponents. "I didn't feel the effect this time".
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Angelique Kerber and Jelena Ostapenko are the only other previous major winners left in the field, and they're part of a group looking to make life hard for Williams in her first Grand Slam tournament back from maternity leave.
Earlier on Friday, Gael Monfils advanced to the fourth round for the first time after knocking out last year's semifinalist Sam Querrey 5-7, 6-4, 6-4, 6-2. She revealed also she has never even spoken to Williams, whom she has long admired.
Williams is the only past Wimbledon champion remaining in the field.
"Serena is my idol, " Rodina said. I know that Phil Brook, the chairman right now, he believes in strict tradition, going back to the '50s, '60s.
So while tennis fans around the world start dreaming, hoping and longing that the two most successful players on planet tennis will renew their rivalry on the sport's greatest stage, there is one person who is definitely not keen on the idea.
Top seed Roger Federer continued his quest for a ninth Wimbledon singles title with a straight-sets victory on Centre Court against Germany's Jan-Lennard Struff on Friday.
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.