BARCELONA -- The last time Barcelona reached a Champions League quarterfinal, Lionel Messi still played for the club and the world was in lockdown due to the COVID-19 pandemic.

During the four years since, there has been just one appearance in the round-of-16, two group stage eliminations and a lot of dwelling on the past. Now, though, as Barça return to the last eight for the first time since 2020 after beating Napoli on Tuesday, there are reasons to look towards a brighter future -- even if this season has not gone entirely to plan after winning LaLiga last year.

Fermín López, João Cancelo and Robert Lewandowski may have scored the goals as Barça beat Italian champions Napoli 3-1 at the Olympic Stadium, earning a 4-2 aggregate win, but it was once again teenagers Lamine Yamal and Pau Cubarsí who were most impressive.

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Yamal, 16, was Barça's match-winner against Mallorca at the weekend and he was often too good for experienced Napoli left-back Mário Rui, who struggled to deal with his pace and trickery. The Spain international led the counter-attack which led to the second goal in the 17th minute, weighting a perfect pass to Raphinha, whose shot off the post was turned home by Cancelo. By that point, López, the 20-year-old midfielder filling in for the injured Pedri and Frenkie de Jong, had already opened the scoring with a well-taken finish as part of a breathtaking Barça start.

Perhaps the only disappointment for Yamal, who already has 13 goal contributions this season, was that he didn't add his own name to the score sheet. He had five shots and came close, one whipped left foot effort curling inches wide in the second half.

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At the back, Cubarsí, 17, won the battle with Iñigo Martínez for a starting berth and did not disappoint on his Champions League debut. He went toe-to-toe with Napoli's danger man Victor Osimhen, proving more than up for the physical battle. With the ball, making just his 12th first-team appearance, he once again excelled, completing 61 of his 68 passes, several of them breaking the lines to set up counter-attacking chances.

"He's incredible, he was the game's best player," midfielder Sergi Roberto said of Cubarsí's performance. "He doesn't stop surprising us, in the last 16 of the Champions League and playing this way ... he's a player who can be here for his whole life."

It is remarkable that these young players are already having such an impact on Barça's senior side. Against Napoli, they became the first club in Champions League knockout stage history to start multiple players under age 18. They have now started three different players under 18 in a Champions League knockout stage match -- the aforementioned duo and Bojan Krkic in 2008 -- overtaking Bayern Munich's record (Jamal Musiala and David Alaba).

It is vindication for La Masia in Barça's hour of need. Since coach Xavi Hernández, who led Barça to a first LaLiga title since 2019 last season, announcing he will step down in the summer, results have begun to improve. They are now unbeaten in nine games in all competitions. In addition to the return of goalkeeper Marc-André ter Stegen from injury and the use of Andreas Christensen as a defensive midfielder, a large part of that is down to Yamal and Cubarsí. López, another player from the club's academy, was also brilliant for an hour before tiring against Napoli.

Lamine Yamal and Fermín López shone as Barcelona defeated Napoli 3-1 on Tuesday. Pedro Salado/Getty Images

There will be caution about just how far Barça can go from here. There were some familiar defensive flaws as they let Napoli back into the game, Cancelo handing the right flank to Matteo Politano, who teed up defender Amir Rrahmani to get the Serie A side back in the game before half-time. There were some nervy moments after the break, but Barça weathered the storm and deservedly sealed their passage into the last eight when substitute Roberto did well to set up Lewandowski.

Lewandowski's 19th goal of the season prompted wild scenes at the Olympic Stadium as the entire Barça bench spilled into the corner to celebrate. This was a significant night for the club: their first Champions League knockout tie at home with fans since the semifinal against Liverpool in 2019 (Napoli and Paris Saint-Germain in 2020 and 2021 were played behind closed doors). There was a terrific atmosphere inside and outside the stadium -- which has not always been the case this season at Barça's temporary home, where they are playing while Spotify Camp Nou is redeveloped -- and, in the end, a result to match.

Qualification also means a €10.6 million payday for the club -- plus revenue from another big home match -- which is important because they had budgeted for a quarterfinal appearance in their annual accounts.

They may not progress any further. Manchester City, Real Madrid, PSG and Bayern Munich may still be out of their reach, but the club are back where they believe they belong. And, to be helped there by academy-developed talent, will make it feel even sweeter. They remain eight points off the pace in LaLiga, but Xavi's dream send-off is still a possibility in Europe.