Roger Federer on Monday became the oldest man to reach the Wimbledon quarter-finals since the dawn of the Open Era in 1968 but then gave a cautious welcome to the return of capacity crowds at the All England Club.
From Tuesday's start of the women's quarter-finals until Sunday's men's final, organisers can drop the 50% capacity rule which has been enforced since the start of the tournament.
The cap was part of an agreement to allow fans to attend as the country comes slowly out of the Covid-19 pandemic which in 2020 caused Wimbledon to be cancelled for the first time since the Second World War.
"I'm still not a hundred percent convinced we are on the other side. I still think there is more to come," said Federer of his fears of another wave.
"Last year in the summer we also felt the same way, super positive, having a few cases here and there.
"It looked very promising, then everything changed again later on in the year."
The All England Club will now allow the 15,000-capacity Centre Court to be full as well as the 12,345-capacity Court One.
"We'll see how it turns out to be now that we have a hundred percent capacity. I mean, it already almost felt like a hundred percent, to be quite honest, because the fans here at Wimbledon, they do such a nice job to make us feel so special," added Federer.
"A hundred percent crowd is going to be incredible. Playing the night session in Paris it was five people. The difference is immense."
Night sessions at the recent French Open were staged for the first time but were played in an almost empty Court Philippe Chatrier due to a government-imposed 9:00pm (1900GMT) curfew.
"I hope it stays this way. I hope that this tournament or the Euro (football championship) or whatever events are going to keep on happening in the future also are not going to create more burden on more families and more people," added Federer.
"So let's enjoy it for what it is now. I feel safe as it's outdoors, a big space. But, yes, it's also very new for me because I haven't played much on the tour yet, so I'm still very, very careful, especially with close contact."
On Monday, Federer, who will be 40 in just under five weeks' time, eased past Italy's Lorenzo Sonego 7-5, 6-4, 6-2 to make the last-eight for the 18th time.
"I felt after the first set I was able to control things. I couldn't be more excited to be in the quarters," said Federer whose match took place on the final 'Manic Monday', so-called because all the last-16 ties in the men's and women's event are played.
From next year, play will be held on the middle Sunday, which has traditionally been the tournament rest day.
"I'm happy to have played in the era that there was a 'Middle Sunday' but it now means more people can come to the tournament.
"It was very special and I really enjoyed it."
In what will be his 58th Grand Slam quarter-final, eight-time Wimbledon champion Federer will face either second seed Daniil Medvedev or Hubert Hurkacz, the 14th seed, for a place in the semi-finals.
Medvedev was leading Hurkacz 6-2, 6-7 (2/7), 6-3, 3-4 when play was halted for the night due to rain.