Marcus Rashford and Christensen were on target as Barcelona began their Copa del Rey defence with a hard-fought win against third-tier Guadalajara.
The La Liga leaders, who defeated rivals Real Madrid in a thrilling final last season to secure a 32nd triumph in the competition, were much changed and made to work for their success.
After a goalless first half, defender Andreas Christensen put them ahead with 14 minutes left, before Rashford struck in the 90th minute to settle the outcome.
Boss Hansi Flick made eight changes to the side that beat Osasuna 2-0 on Saturday to maintain their four-point lead in the championship over Real Madrid.
Barcelona came close to taking the lead inside six minutes when Guadalajara goalkeeper Dani Vicente almost parried Eric Garcia’s audacious effort from close to the halfway line into his own goal.
But even with more than 80% possession in the opening period, that was as close as the visitors came to a breakthrough, with both Rashford and Lamine Yamal struggling to make an impact.
But with their 19th shot of the night, Barcelona led when Christensen headed Frenkie de Jong’s cross past Vicente.
England forward Rashford, hoping to turn his loan from Manchester United into a permanent deal, sealed the victory when he latched on to a pass from Yamal and rounded the keeper to finish calmly.
Deportivo La Coruna, Elche, Real Sociedad and Valencia joined Barcelona in the last 16 with wins on Tuesday night, while Real Madrid visit Talavera on Wednesday.
Next up for Flick’s men is a trip to Villarreal in La Liga on Sunday (15:15 GMT).
(BBC Sport)
