Manchester United suffered a 1-0 loss at Brann in the first leg of their women's Champions League third qualifying round tie on Thursday, while Real Madrid beat Eintracht Frankfurt in Germany.
Marc Skinner's United dominated for long periods in Norway but were hit by Ingrid Stenevik's close-range header in the 76th minute from a Signe Gaupset free-kick.
The English club will need to overturn a one-goal deficit in the return match in a week's time to reach the inaugural 18-team league phase.
United have never played in the tournament proper before.
Real Madrid, who lost to eventual champions Arsenal in last season's quarter-finals, will defend a 2-1 lead next week against Eintracht thanks to goals from Sweden midfielder Filippa Angeldal and Denmark's Signe Bruun.
Former semi-finalists Paris FC were held to a goalless home draw by Austria Vienna, while Atletico Madrid drew 1-1 with Hacken in Sweden.