Key takeaways: 

• Ferran Torres's goal assured that Barcelona's undefeated run continues, extending to 8 December.
• Ferran Torres netted for Barcelona as they battled back at Eintracht Frankfurt to achieve a tie in the first leg of their Europa League quarter-final.

Ansgar Knauff's excellent long-distance attempt soon after half-time raised the possibility of a first Barcelona loss since December.

But Torres connected brilliantly with Frenkie de Jong before netting with a low drive.

The hosts had defender Tuta getting a red card late, but Barca could not capitalize.

That sent-off for two bookings limited a busy evening for English referee Michael Oliver. He cited Frankfurt a penalty before changing his mind after being sent to the pitchside screen.

Ex-Manchester City forward Torres's goal means the Spanish team, now undefeated in 22 matches and rejuvenated under boss Xavi, will be favorites to go to the semi-finals when they face again for the second leg at Nou Camp next Thursday.

The winner will meet either West Ham or Lyon in the semi-finals, with that draw evenly poised after a 1-1 first-leg draw at London Stadium.