It was the sixth time McLaughlin-Levrone had broken the world record, lowering her previous mark of 50.65 set at the U.S. trials in June.
Lyles, who had been bidding to complete a 100m-200m double in Paris, was taken off the track in a wheelchair following the race, won by Botswana's Letsile Tebogo.
The 26-year-old, who had claimed virtually every other title in an utterly dominant half decade including three world championship gold medals, clocked 12.99 seconds.
A tense game ended all square at 1-1, with fourth-quarter goals in quick succession from Dutch captain Thierry Brinkman and Germany's Thies Prinz.
Nadeem threw an Olympic record of 92.97 metres for victory, India's defending champion Neeraj Chopra taking silver with 89.45. Grenada's Anderson Peters claimed bronze with 88.54m.
Marathon swimming is set to get underway amid concerns over water pollution in the river Seine.
There will be 21 medals up for grabs with the bulk of them being given out in athletics.
"The last hurrah, I'm done. I've always said I want to retire a champion, that's it," Harrington told Irish national broadcaster RTE.
Alfred is seeking to emulate Jamaica's Elaine Thompson-Herah, who did the 100m-200m double at the Rio 2016 Games and at the Covid-delayed Tokyo Olympics.
Nadal, a singles gold medallist at the 2008 Olympics, is playing in his final Games having also won doubles gold in Rio in 2016, while Djokovic was a bronze medallist in singles in 2008.
The Italian said he was "sad and disappointed" to drop out, adding that he had started feeling unwell on Monday after a practice week in Monaco.
France deployed about 1,000 police officers backed by Israel's own internal security service, Shin Bet, to welcome thousands of supporters for the evening kick-off. They cordoned off the streets around the Parc des Princes in western Paris and set up a perimeter a few kilometres away from the stadium
"I can't explain what happened. We spent about an hour and a half in the dressing room where they never told us what was going to happen," Mascherano told reporters.
The dealers have promised a steady supply of wares, but warned prices may go up and delivery wait times too under the weight of tens of thousands of security forces and heavy demand.
World Champions Argentina will be in action on day one as they take on Morocco in the opening match, starting at 7pm (Bangladesh Time)
The 37-year-old, a two-time Olympic champion, is planning to play in the singles and doubles at his fifth Games.
The ceremony, staged for the first time outside a stadium, will involve around 80 boats ferrying international athletes on a six km (3.7 mile) route along the river Seine towards the Eiffel Tower, said the official, Lambis Konstantinidis.
Both players had indicated their desire to participate in the Paris Games, but their Spanish clubs -- Real Madrid where Mbappe, 25, is set to play next season and Atletico for 33-year-old Griezmann -- have said they will not release them.
Iraq will join Japan and Uzbekistan at the Paris Games.