De Zerbi claims Brighton were affected by atmosphere at Marseille
The hosts scored twice in a minute during the first half at Stade Velodrome before Brighton fought back after the break, with Joao Pedro's late penalty salvaging the draw.
De Zerbi said his side were punching above their weight on the European stage.
"I know we are not a big team yet. We are a small team, a small club," he told reporters on Thursday. "We've reached this European competition playing very well, showing the incredible qualities of the players.
"It's possible we suffered with the atmosphere a bit too much. It's the first (away) game in Europe for Brighton, for the players, for the club, for the fans.
"We have to adapt. We have to get used to playing in this competition."
The draw followed back-to-back defeats for Brighton, who lost 1-0 to Chelsea in the League Cup before being thrashed 6-1 at Aston Villa in the Premier League on Saturday.
"I'm really proud of the performance today, of the players," De Zerbi said. "After the defeat 6-1 at Villa Park and the second goal to close the first half at 2-0, this reaction is incredible."
Brighton, who remain bottom of Europe League Group B, return to domestic duty on Sunday with the visit of Liverpool in the Premier League.
