Barcelona and PSG win away in Women's Champions League
Spanish champions Barcelona had 34 attempts on goal but needed a 72nd-minute strike from Salma Paralluelo to take the upper hand in the tie ahead of next week's second leg at home.
Norway international Caroline Graham Hansen put Barcelona ahead early on, but Brann resisted in the face of constant attacks and Cecilie Kvamme squeezed home an equaliser before half-time.
Paralluelo eventually put Barcelona back in front in Bergen with a sharp turn and finish - her competition-best sixth goal - to keep the favourites on course for the last four.
Barcelona have won two of the last three editions and finished runners-up in 2022, while Brann are appearing in Europe for only the second time.
Paris Saint-Germain secured a 2-1 victory away to Swedish club Hacken in Gothenburg earlier in the day.
Goals from defender Eva Gaetino and forward Tabitha Chawinga ensured PSG return to France with the advantage after Rosa Kafaji had equalised, heading in the rebound after her penalty was saved.
"It's good to leave here with a win, few teams have done it so far so it's positive," coach Jocelyn Precheur told PSG TV.
"We were quite careful at times but in matches at the top level I feel we could be more consistent and manage tougher periods better. I think we can be better in the second leg."
Hacken are the first Swedish team to reach the last eight since the group stage was introduced in the 2021/22 season. PSG are two-time runners-up, having reached the final in 2015 and 2017.