Alan MacDonald described his Test debut as "bittersweet" after Scotland blew a 6-0 half-time lead against Argentina to end Andy Robinson's 100% record in charge.
Edinburgh flanker MacDonald was handed his first cap by Robinson for the final autumn international at Murrayfield but was unable to prevent a second-half fightback from the Pumas, who triumphed 9-6.
It was a fourth straight victory in the Scottish capital for Argentina, who have not lost there since 1990, and denied their opponents a first clean sweep of November Test wins since 2002.
MacDonald, 24, said: “It is a bittersweet moment. Obviously, it’s a great honour to get my first cap but I’m just bitterly disappointed that we couldn’t get the win.
“The two halves, I thought, were very contrasting. The first half, we had a bit of possession and were attacking a lot.
“Maybe we should’ve put some more points on the board. Second half, we were having to dig a little bit more.”
Scotland went into the game having won their opening two matches under Robinson against Fiji and Australia.
The latter victory - a first over the Wallabies for 27 years - was achieved despite their opponents completely bossing possession and territory.
Scotland turned that statistic on its head in the first half against the Pumas but failed to make the most of their dominance, with two Phil Godman penalties all they had to show for their efforts.
MacDonald said: “When you’ve got pressure, you need to turn it into points.
“We probably should’ve scored a few more in the first half with the amount of ball possession that we had.”
The turning point arrived shortly after the break when Nathan Hines was sin-binned for a dangerous tackle on Gonzalo Tiesi.
Martin Rodriguez kicked the resulting penalty and another one while Scotland were down to 14 men before completing the comeback with a well-worked drop goal three minutes from time.