A game of cricket that broke out on a street in Peckham was described as a "sweet and exuberant moment of joy".
Revellers were seen just after 10pm by Peckham Rye Station with a bat and ball surrounded by a large crowd.
"My guess was that it had recently started as everyone was kicked out of the local pubs and bars," James Jones, a documentary maker who caught the game on video, told the PA news agency.
"I was there for about 10 minutes and it was still going strong."
Mr Jones, himself from Peckham, said that the game felt like a "moment of joy".
"Obviously on social media people are projecting all sorts of views onto it," he told PA.
"Being there, it felt like a very sweet and exuberant moment of joy. And we could all do with some more joy at the moment!"
London Mayor Sadiq Khan has urged Londoners to wear a mask, as the number of people in hospital with coronavirus increased across every part of England on Saturday.
A further 15,166 lab-confirmed cases of coronavirus in the UK were reported on Saturday, and 81 more deaths were confirmed of people who died within 28 days of testing positive for Covid-19.
Mr Khan posted on Twitter on Sunday: "We live in a time when the simple act of wearing a mask could save countless lives."