Arsenal boss Arsene Wenger said Gabriel’s pace and previous experience at right-back convinced him to deploy the Brazilian there in the 3-1 win against Bournemouth.
Former Villarreal defender Gabriel, usually a centre-back, came on for Mathieu Debuchy, who went off with a hamstring injury just 16 minutes into his first appearance for the Gunners for a year.
“When I picked the squad I imagined that something could happen to Debuchy,” Wenger said at this post-match press conference.
“I had Francis Coquelin ready to play right-back as well because he can play there, but I went for Gabriel because he’s a defender and is very quick.
“He adapted well. I watched tapes of him playing full-back at Villarreal. On two or three occasions he played at left-back and I found just one tape of him playing at right-back.
“He was playing in Brazil and I must say that it was not super convincing, but today he did well.”
Alexis Sanchez scored twice and Theo Walcott also netted as Arsenal ended a run of three successive draws.
But the win was marred by the injury to Debuchy, who looks set for another spell on the sidelines.
“He thinks it’s a severe one. Don’t go too far because I have to speak to medical people, but you can only assess it really after 48 hours,” Wenger said.
“You have to let it bleed and usually they have an MRI scan 48 hours later to see how big the damage is.”