By SABC Sport
17th March 2023
A 2-2 draw in Lisbon a week ago left this last-16 tie finely poised and it would go all the way at the Emirates Stadium, Sporting advancing 5-3 on penalties following a 1-1 draw after extra-time.
The visitors were perfect from 12 yards but Martinelli's tame effort was saved in the first ever shoot-at the Emirates.
As Kim Kardashian watched on, the reality for Arsenal is that all their hopes of a trophy this season now rest on their Premier League title charge, which continues at home to Crystal Palace on Sunday.
Granit Xhaka's first goal since October had Arsenal ahead but they failed to build on that advantage before conceding a spectacular equaliser, reminiscent of the goal Nayim scored against the Gunners in the 1995 Cup Winners' Cup final as Pedro Goncalves struck from over 49 yards out.
Substitute Leandro Trossard saw a shot turned onto the woodwork in the first half of extra-time before Manuel Ugarte was sent off, shown a second yellow for a lunge on Bukayo Saka.
The pressure ramped up in the shootout as the first seven takers all converted before Martinelli failed to do so, allowing Nuno Santos to smash home the decisive kick.
Mikel Arteta named a strong XI despite fighting on two fronts, with the Premier League title race no doubt his top priority as the Gunners sit five points clear at the summit - Gabriel Jesus back in the starting line-up for the first time since returning from knee surgery.
He lost Takehiro Tomiyasu to injury with less than 10 minutes on the clock as he limped off to be replaced by Ben White.
Jesus had his first sight of the Sporting goal with 15 minutes on the clock but could not steer home a Reiss Nelson cross
Arsenal went ahead inside 20 minutes, Jorginho with a fine pass to Martinelli, whose shot was saved by Antonio Adan but Xhaka made no mistake in turning home the rebound.
While things were going well in front of goal, Arsenal lost their second player to injury within the opening quarter of the contest when William Saliba limped off and Rob Holding came on in the centre of defence.
Jesus was again prevented from marking his comeback with a goal as Adan made a brilliant low stop to keep out the Brazilian's effort on the half hour.
Jesus was replaced by Trossard at half-time but Arsenal's game was still not clicking like it has done in the Premier League of late and the tie was soon levelled in remarkable circumstances.
Sporting won the ball in midfield and Goncalves spotted Ramsdale off his line, brilliantly lobbing the England goalkeeper from just inside the Arsenal half.
Arteta responded by bringing on the big-hitters as Saka and Thomas Partey were introduced in the immediate aftermath of the Sporting goal.
Ramsdale will have been unhappy to concede such a goal but made himself big to keep out Marcus Edwards when the former Tottenham man burst through one on one as the visitors began to dominate.
Neither side could find a winner in the 90, however, as the tie went to extra-time giving Arsenal an additional 30 minutes of football Arteta would have wanted to avoid.
Trossard forced a smart save from Adan, who tipped the Belgian's effort onto the post as the hosts looked to turn the tide.
Skipper Martin Odegaard was introduced, his first role a de facto cheerleader as he whipped the home fans into a frenzy for the closing stages.
Adan was again on hand to theatrically palm a Gabriel Magalhaes header over with the Brazil defender seeing his effort from the resulting corner hacked off the line.
Sporting were beginning to tire and their tackles became more desperate, Ugarte shown a second yellow card after clattering into Saka as Arsenal were the side pushing to win it.
The tie would ultimately be decided by a penalty shootout, Jerry St Juste was first up for the visitors and smashed his spot-kick past Ramsdale, who guessed the right way.
Odegaard then stepped up for Arsenal and calmly slotted home, Ricardo Esgaio then re-establishing the lead before Saka was the next Arsenal man to tuck away from 12 yards.
Ramsdale got a hand to Goncalo Ignacio's effort but could not keep it out as Trossard continued the scoring run to make it 3-3.
Arthur Gomes' penalty sneaked in as Ramsdale again came close to saving, with Martinelli seeing his saved by Adan to put Sporting on the cusp.
Santos made no mistake as he smashed home to send the visitors through 5-3 on aggregate, with Arsenal still without a home knockout win in Europe since May 2019.