The Polish side's French centre-back Steve Kapuadi scored the only goal of the match with a header in the 23rd minute in Warsaw on Thursday.
Meanwhile, Polish champions Jagiellonia Białystok beat Danish side FC Copenhagen 2-1 away from home in their Conference League opener on Thursday night.
Legia and Jagiellonia will each face six different opponents in the league phase of the 2024/2025 UEFA Conference League until December 19, Polish state news agency PAP reported.
The top eight sides in the league phase of the new-look Conference League will qualify automatically for the knockout stages, while the teams finishing in ninth to 24th place will compete in a two-legged play-off to secure a place in the last 16 of the competition.
Teams ranked 25-36 will be eliminated from the competition, run by European football governing body UEFA.
Source: IAR, PAP, polskieradio24.pl, skysports.com