Hansi Flick was relieved to survive a "crazy game" as Barcelona thrashed Newcastle United 7-2 to move into the Champions League quarter-finals.

A chaotic nine-goal thriller in the second leg secured an 8-3 aggregate win for Flick's side, who will face either Tottenham or Atletico Madrid in the next round.

Raphinha scored two and set up another pair of goals, though Barcelona were hanging in the balance after Anthony Elanga's first-half brace made it 2-2 on Wednesday.

Lamine Yamal's penalty on the stroke of half-time calmed the nerves before Fermin Lopez's 51st-minute finish eased the LaLiga leaders out of sight, much to Flick's relief.

"It was a crazy game. We weren't sharp in the first half, but we improved in the second. We kept possession. That third goal of ours gave us the chance to get back into the game," the Barca head coach said.

Robert Lewandowski added a late brace, along with a cool finish from Raphinha to round off the scoring, to seal the biggest margin of victory for a Spanish side against an English opponent since May 1966.

"In the first half we played a lot of direct balls and lost possession too often," Flick added.

"Against an opponent so good at transitions, that wasn't what we wanted. We had talked about controlling the game more in the second half and playing better in that low block.

"They have a day off tomorrow, which they've earned."

Raphinha now has 33 goal involvements (19 goals, 14 assists) in 33 Champions League games; only Erling Haaland (22), Ruud van Nistelrooy (28), Kylian Mbappe (30), and Luis Suarez (31) reached 30+ in fewer appearances in the competition (Neymar level with Raphinha on 33).

"With the fans supporting us like this, it's difficult for anyone to beat us at home," Raphinha said after the hammering.

Newcastle's seven goals conceded is the joint-most ever by an English team in a major European competition match, along with Tottenham in their 7-2 defeat to Bayern Munich in October 2019, but Raphinha says Barca did not take their opponents lightly.

"We knew it would be quite difficult. They're a very physical team that can make things tough," the Brazilian added. "We were calm; we just needed to control the game more.

"In the first half, we lost possession a lot that we shouldn't have, but in the second half, we controlled the game better. The fourth goal came quickly, and that gave us peace of mind."

"Now we have to prepare for the weekend's match. After the break, we'll think about the following matches."