John Hughes’ side started the Europa League second qualifying round first-leg tie well and their composure in passing the ball about belied their lack of European experience.
However, a Constantin Budescu free-kick after 24 minutes was enough to separate the sides and dampen the enthusiasm around Caley’s first appearance against European opposition.
Romanian side Astra, who played Scottish champions Celtic in the group stages of the competition last season, looked sloppy in possession in the early stages and Ryan Christie’s first effort after eight minutes was deflected wide.
Despite Inverness forcing the issue at the Caledonian Stadium, it was the away side who took the lead through a contentious free-kick when debutant goalkeeper Owain Fon Williams could only get a hand to Budescu’s brilliant effort from just outside the box.
The Scottish Cup holders were the better side in the first half but chances were at a premium. However, Aaron Doran did bring out a good save from Silviu Lung Jr in the Astra goal after 35 minutes following some neat build-up play.
Williams was then the hero as he managed to parry Budescu’s stinging shot from 25 yards to ensure the visitors did not double their lead before the interval.
Inverness controlled parts of the second half but again failed to carve out many clear-cut chances.
Doran was again denied by Lung Jr when the goalkeeper pushed his effort from the edge of the box round the post.
Brazilian William went close for the visitors with 22 minutes remaining after getting on the end of Budescu’s disguised pass but his effort struck the post.
Doran and new signing Dani Lopez had decent chances to get a goal back for Inverness but their finishing was fairly tame.
There was a rapturous welcome for Inverness captain Richie Foran, who came off the bench after missing all of last season through injury, but he could not inspire his side to find an equaliser and they will travel to Romania next week needing to overturn a 1-0 deficit.