Mikel Arteta revealed Gabriel asked to take the decisive fifth penalty in Arsenal's Champions League final shootout defeat.
Paris Saint-Germain defended their European crown with a 4-3 win from the penalty spot, denying Arsenal a first Champions League success.
The Gunners made the perfect start to the match when they took the lead through Kai Havertz inside six minutes.
However, Cristhian Mosquera brought down Khvicha Kvaratskhelia midway through the second half to allow Ousmane Dembele to equalise.
It ultimately went all the way to penalties and Arsenal were forced to improvise away from their usual takers.
Viktor Gyokeres has taken ownership of penalties this season but otherwise Arsenal's three takers in recent seasons have been Martin Odegaard, Bukayo Saka and Kai Havertz.
That trio were unavailable for the shootout. Odegaard and Saka were replaced within the 90 minutes and Havertz came off before extra-time, after treatment on the touchline determined he was unable to continue.
Gyokeres, Gabriel Martinelli and Declan Rice converted from the spot, but Eberechi Eze missed the target and the pressure then fell on Gabriel's shoulders.
He stepped up to the spot knowing he had to score to extend the shootout - the centre-back lashed his penalty over the bar.
"He wanted to take number five," Arteta said.
"Obviously we have prepared and trained this moment. Normally the penalty takers would be Bukayo, Martin and Kai for sure.
"Today we knew that if we go to extra-time and penalties, the penalty takers would be different players.
"Still with the quality - when you have Ebs taking penalties in training, he doesn't miss any. But then you have to do it in this moment.
"We were unfortunate not to have the same precision and efficiency that they had and that's the reason we haven't won it."
