Morgan Rogers fired Aston Villa into the Champions League last 16 as the England forward's hat-trick inspired a dramatic 4-2 win against Celtic on Wednesday.
Unai Emery's side needed a victory in the 'Battle of Britain' at Villa Park to wrap up automatic qualification via a top eight finish on the final evening of the league phase.
They were on course after Rogers became the first player to score twice in the opening five minutes of a Champions League game.
In a pulsating tie, Celtic striker Adam Idah ended a 14-game goal drought stretching back to November as he netted twice in quick succession just before halftime.
But, just hours after Arsenal reportedly made a £60 million ($74 million) bid for Ollie Watkins, the 29-year-old restored Villa's advantage after the interval.
Watkins also missed a penalty, but Rogers netted the first treble of his career in the final seconds as the 1982 European Cup winners finished in eighth place.
After the final whistle, Villa's players gathered on the pitch to check the results of the other games that affected their fate before they could finally celebrate.
Villa will await the winners of the eight two-legged knockout play-off ties featuring the clubs ranked from ninth to 24th in the league phase.
Back in the Champions League for the first time since 1982-83, this was another landmark moment for Villa, who memorably beat Bayern Munich earlier this season.
Scottish champions Celtic were already guaranteed a spot in February's play-off round after last week's win over Young Boys.
Brendan Rodgers' team, in the knockout stages for the first time in 12 years, finished 21st place and will face holders Real Madrid or Bayern Munich in the play-offs, with the opponents to be decided in Friday's draw.
Supporters on the Holte End set the tone for a memorable night by unveiling a Tifo banner of snarling Black Sabbath singer and noted Villa fan Ozzy Osbourne before kick-off.
- Villa revival -
In the first competitive game between the clubs, Rogers tried to ensure Villa fans wouldn't feel paranoid about their team's top-eight hopes with a blistering start.
Jacob Ramsey surged into the Celtic area in the third minute and cut the ball back to Rogers, who guided a clinical finish past Kasper Schmeichel from 12 yards.
Villa doubled their lead when Watkins picked out Rogers, who set his sights from the edge of the area and unleashed a superb strike that took a slight deflection as it arrowed into the top corner.
Villa midfielder John McGinn, a boyhood Celtic fan, played an accidental role in sparking the visitors in the 36th minute when his attempt to block a cross only guided it towards Idah, who alertly twisted to hook home from close-range.
Just 145 seconds later, Celtic were level with a superbly crafted goal.
A flowing move sliced open the Villa defence and Reo Hatate's pass teed up Idah to fire into the roof of the net.
Idah was the first player from the Republic of Ireland to score twice in a Champions League game since Liverpool's Ronnie Whelan in 1984.
Shell-shocked Villa needed to regroup at halftime and their renewed pressure paid off on the hour.
Ramsey's burst on McGinn's ball took him beyond the Celtic defence for a squared pass that gave Watkins the chance to lash home from 12 yards.
Watkins wasted a golden opportunity to put Villa out of sight moments later after Auston Trusty's foul on the striker conceded a penalty.
McGinn and Watkins debated who would take the penalty, with the latter getting the nod, only to slip during his run-up and scuff his shot embarrassingly wide.
Fortunately for Watkins, that blunder was not costly as Rogers completed his treble in stoppage time with a cool close-range finish.