Supporters attended elite competitive football in the UK for the first time since March as Cambridge beat Fulham Under-21s 2-0 in the EFL Trophy.
A crowd of 862 were at the Abbey Stadium for the sport's first test event since the coronavirus lockdown.
Measures were in place for social distancing and masks were worn, while shouting and singing were discouraged.
Cambridge will host a second pilot on Saturday, with 2,500 fans allowed at their League Two opener with Carlisle.
UK Prime Minister Boris Johnson has previously said that spectators could return to stadiums in England from October, though there has been a recent rise in virus cases - which has prompted a ban on social gatherings of more than six people which was announced on Tuesday evening, though organised team sports are exempt.
'It was just about normal' - fan reaction
It took only a minute of fans being back in a stadium for the first ironic cheers and chants of "who are you" as a Fulham youngster ran the ball out of play.
And there was loud applause and a few shouts of joy on kick-off as those in attendance realised the magnitude of the occasion, while some could not contain their delight as a Tom Knowles free-kick gave Cambridge the lead.
"Apart from the face masks which you have to wear all the time, it was just about normal," U's fan Ashley Whiskin told BBC Sport after the game.
"It might be a bit different when there's a last-minute winner in the league but I think everyone behaved themselves.
"I felt OK - perhaps there were a few supporters closer than the two-metre rule but I don't think people are going to be penalised for that."
Songs from the stands were initially in short supply as supporters heeded requests, but noise levels grew in the second half as those on the terraces settled back into their surroundings.
And when Paul Mullin slotted a second for the hosts late on, the crowd reaction was more like we are used to hearing in stadiums across the world.
"It was odd - we just haven't been used to having that many people around us like that," said home supporter Richard French.
"But I got used to it fairly quickly and I think we're going to have to live with it for a very long time."
Ticket holders were sent a code of conduct before the match, with regular reminders to maintain social distancing over the public address system, while fans stayed in position at full-time until guided out in small groups by stewards.
Heavy EFL Trophy defeats for top-flight duo
Elsewhere, there were a couple of heavy defeats for Premier League Under-21 sides in the first group games, with the youngsters of Leeds United and Aston Villa both losing by seven-goal margins.
On-loan Chelsea striker Tariq Uwakwe scored four goals on his debut as League One side Accrington Stanley hammered Leeds Under-21s 7-0.
Uwakwe tapped home an easy opener inside four minutes and his second helped the hosts lead 5-0 at the break. A rasping strike sealed his treble and he added a fourth in the latter stages.
Aston Villa Under-21s were 8-1 losers away against Sunderland, with new signing Danny Graham scoring on his debut after coming on in the second half.
Chelsea Under-21s lost 2-1 away against Oxford United, whose boss Karl Robinson signed a new contract before the game, but there were victories for the under-21 sides of both Manchester City and Arsenal.