Arsenal has been knocked out of the Europa League after a penalty shoot-out defeat by Sporting Lisbon, on a disappointing night at the Emirates Stadium.
The Premier League leaders took the lead in the first half when Granit Xhaka pounced on a rebound to give his side the lead.
But Pedro Goncalves scored a quite memorable goal from near the halfway line, when he spotted Aaron Ramsdale off his line, before producing an outstanding finish.
Gabriel Martinelli was denied by an inspired Antonio Adan in the shoot-out to send the Portuguese club through to the quarter-finals.
Takehiro Tomiyasu and William Saliba were taken off with injuries, on what could prove to be a costly night for Mikel Arteta.
Story of the match
There was a big boost for Arsenal pre-match as Gabriel Jesus, who hadn't been named in a Gunners starting line-up since November 12, was handed a start.
Tomiyasu, Jorginho, Fabio Vieira and Reiss Nelson also came into the side that beat Fulham 3-0 on Sunday.
Mikel Arteta revealed yesterday that he wants to refer to his substitutes as 'impacters', and with that in mind, Bukayo Saka, Martin Odegaard and Leandro Trossard were named on a strong bench.
The former Tottenham man Marcus Edwards was selected in the Sporting side, along with Francisco Trincao, who spent last season on loan at Wolves.
With the tie evenly poised at 2-2 following a dramatic first leg, both sides knew a fast start was needed if they were to make it to the quarter-finals.
Arteta was forced into an early change when Tomiyasu overstretched, and Ben White replaced the Japanese international.
The Portuguese outfit had the first attempt at goal after 13 minutes when Trincao cut in from the right-hand side, but his left-footed strike went just past the post.
Arsenal responded almost immediately as Nelson delivered a wicked cross from the right, but Jesus' effort was scrambled away by Adan in the Sporting goal.
But minutes later, they were in front. Jorginho played a delightful ball in behind for Martinelli to run onto, his shot was saved by Adan but the rebound fell to Xhaka, who fired the ball home.
In the aftermath of the goal going in, Rob Holding was being brought on for Saliba, who limped off, which will be of concern to Arteta.
On 30 minutes, Jesus reminded everyone just what a miss he's been for Arsenal as he wriggled into the penalty area brilliantly before his low strike was saved by Adan.
The visitors continued to offer a threat though, and they went close twice before the break as long-range efforts by Jeremiah St. Juste and Manuel Ugarte were just off target.
Trossard replaced Jesus at the start of the second half in what seemed like a planned change by Arteta, as Arsenal gradually try to get the Brazilian back up to full match sharpness.
Ruben Amorim's men started the half as the brighter side and were rewarded with an unbelievable equaliser on 62 minutes.
Goncalves picked up the ball slightly in the Arsenal half, he spotted Ramsdale off his line and produced a sublime effort which looped over the England international and into the net.
Thomas Partey and Saka were brought on as the Gunners tried to shift the momentum back in their favour.
But it was the Portuguese side who went close again, as Edwards was played through one-on-one with Ramsdale but the 24-year-old made an excellent stop low to his left.
Apart from that chance though, the introduction of Partey in particular had definitely made an impact because Arsenal began to get a foothold back in the game.
They struggled to create any clear-cut chances, however, with both sides having to settle for extra time.
The hosts had the first chance of the extra 30 minutes when a sloppy back pass put Trossard through on goal, but Adan managed to tip the ball onto the post.
Odegaard was introduced soon after to a rapturous reception from the home fans, as the crowd hoped that he would provide the spark that Arsenal needed.
With three minutes remaining in extra time and with a penalty shoot-out on the horizon, Arsenal were denied again by Adan as he kept out Gabriel's header.
Ugarte was shown a second yellow card for a nasty challenge on Saka, but it didn't really have too much impact as there were just seconds remaining.
It was Adan who would be the hero for Sporting in the shoot-out as he kept out Martinelli's tame penalty to put the Portuguese side on the brink of the quarter-finals.
Nuno Santos struck the final spot-kick beyond Ramsdale, which led to jubilant scenes amongst their players and fans.
It was a disappointing night for the Gunners, due to the result and the injuries to Tomiyasu and Saliba, but the North London outfit needs to respond quickly as they host Crystal Palace at home on Sunday in the Premier League.
Player of the match - Antonio Adan
A special mention to Goncalves, whose goal will live long in the memory but Adan was the real reason why Sporting progressed tonight.
Excellent saves from Jesus, Gabriel and Trossard kept Arsenal at bay and there was nothing he could really do to prevent Xhaka's first-half goal.
He then thwarted Martinelli in the shoot-out to end the English side's European campaign for another season.