Barcelona manager Hansi Flick has opened up about the crucial half-time tactical tweaks that sparked his side's incredible comeback against Newcastle in the Champions League. After a chaotic and difficult first half, the German coach's specific instructions completely changed the momentum, paving the way for a dominant second-half display and a quarter-final spot.The match began frantically. Raphinha opened the scoring in the sixth minute, but Anthony Elanga equalised in the 15th minute. Marc Bernal quickly restored the Catalan giants' lead, only for Elanga to strike again to make it 2-2. Just before the break, a Lamine Yamal penalty gave the hosts a 3-2 advantage. While the tie was fairly close on aggregate and little separated the two sides at the break, the second half was total dominance from Barca. Fermin Lopez found the net in the 51st minute, followed by a quickfire double from Robert Lewandowski in the 56th and 61st minutes. Raphinha then completed his brace in the 72nd minute, sealing a spectacular 7-2 victory and an 8-3 aggregate triumph.Addressing the media, Flick revealed the exact tactical adjustments demanded in the dressing room that transformed the team's performance. The manager explained his decisive intervention: “We played too directly in the first half. They're good on the counter-attack and we weren't doing well. We managed to control the game more in the second half."The first half was very tough. We knew they would press. We scored two goals, but we had a lot of ups and downs. We made it 3-2, and at halftime, I told the players that we were constantly pushing forward. I told them we had to press them, then control the ball and get in behind them when we could. And it worked out well."The German tactician also highlighted the importance of his veteran striker, Lewandowski, who broke Lionel Messi's record by scoring against his 41st different Champions League opponents. "It has not been an easy situation because he and Ferran Torres are measured by goals," Flick noted. "I am happy that he has scored again. I'm glad he scored in the Champions League. We have many very important players for us. He has experience; and he is a great goalscorer." Add GOAL.com as a preferred source on Google to see more of our reportingBarcelona now turn their focus back to La Liga, sitting comfortably at the summit. They host Rayo Vallecano this weekend before facing Atletico Madrid on April 4. Diego Simeone's side are also their next Champions League quarter-final opponents, with the first leg taking place just days after their domestic meeting. "The next round will be very difficult," Flick cautioned. "We have to go step by step, game by game. It's what we did last season and what we're going to try to do this one."