Having fallen eight points adrift at the end of the first half when they were reduced to 13 men, Wales fought back bravely after the break and scored the try of the game deep into injury time to bring the deficit back to two points.
"It wasn't the result we wanted. We believed all week we could get a win here," said Jenkins, who is missing 21 players and blooded four new caps during the game.
"I am full of admiration for the spirit and intent of this young team. They did everything they could to win that game and I couldn't have asked more of them," he added.
"We came back well after those two yellow cards. We left it late to score a fantastic try to get within two points and it was just a shame there were five more minutes left to play.
"It was a huge effort and we aren't out of this Test series. We are going to Buenos Aires realising we can win."