Jules Koundé scored twice in three second-half minutes to strengthen Barcelona's hopes of making it through to the Champions League knockout stages with a 2-1 win over Eintracht Frankfurt.

Barca looked in trouble at halftime at the Spotify Camp Nou as they were trailing to Ansgar Knauff's first-half strike.

But Koundé came to the rescue with a pair of headers early in the second half to ensure the Spanish outfit remain in striking distance of the top eight in a heavily-congested league table.

"I was really happy because we show the team two situations, how we want to do it," Hansi Flick said after the match. "We have the space we need to cover and they made it. It's always the same with the team, they know what to do, and they do it. At the moment it works. I am really happy about this. I am happy we came back. Jules with his mentality is absolutely important for us."

Flick's side had the ball in the back of the net early on as Robert Lewandowski finished emphatically, but it was chalked off as Raphinha strayed offside in the build-up.

The hosts continued on the front foot and Gerard Martín forced Frankfurt goalkeeper Michael Zetterer into a flying save.

That proved important as Frankfurt took a surprise lead in the 21st minute.

Nathaniel Brown broke forward at speed and picked out Knauff, who outmuscled Alejandro Balde and fired into the bottom corner.

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Barcelona pushed for a leveller, but were held at bay by the German side, who defended resolutely.

And they could have taken a two-goal lead into the second half as Knauff made headway down the right and squared for Ellyes Skhiri, whose 18-yard effort curled just over.

The LaLiga leaders brought Marcus Rashford on at the break and the Manchester United loanee had an instant impact.

"In the first half we had not the right position, so we changed a bit along the way," Flick added. "It was important to have Marcus on the pitch, he gives us the width, which was very important. It took two set pieces to come back, but it's good, it's part of the game."

After teeing up Raphinha, who fired over, he created the 50th-minute equaliser by whipping in a delicious cross which Koundé headed home.

Three minutes later, the turnaround was complete as Koundé doubled his tally.

This time it was Lamine Yamal who was the creator and the Frenchman nodded in at the far post.

Yamal was never far from the action and whizzed an effort just wide as the hosts looked for a third goal which would have killed the game. Yamal was on a yellow card and seemed annoyed when he was substituted late in the game -- a situation Flick laughed off.

"Next time, he sits on the bench. It's not a problem for me. It's Lamine. It's like it is," Flick joked about his superstar. "He gets the yellow card, five minutes to go, we have to make a change. Everyone wants to stay on the pitch, to play 90 minutes or 100 minutes. He's young. It's a good attitude. I have not a problem with that. I understand. I was a player. Maybe I didn't show it like Lamine, but he's another player, another level, so I accept it."

Information from PA and The Associated Press was used in this recap.