Barcelona boss Ernesto Valverde praised Ansu Fati as a "natural" as the teenager became he youngest goalscorer in Champions League history to knock out Inter Milan.
Inter were dispatched 2-1 at the San Siro with Carles Perez scoring on his debut in the competition to seize the lead before Romelu Lukaku replied, but 17-year-old Fati struck the winner in the 87th minute.
Valverde is now determined to lift the trophy, saying: "We feel obliged to win this competition. We want to win every single match and that's what we've achieved here.
"Carles has the nose for more goals and strikes the ball really nicely. Ansu is a born scorer and although he's had some niggling pain, we wanted him to have some minutes.
"That it's a Barca lad who's the youngest ever scorer in this competition delights us.
"We're thrilled because Inter are a really demanding rival. We played to win and my players, many of whom were making a debut of some kind, responded by showing competitive mettle."
Fati combined with fellow substitute Luis Suarez before drilling the ball home with a superb strike.
"I played the give and go with Luis and when I scored the stadium just went silent. I'm super happy!" Fati said.
"It's a dream. Everything seems to be going at high speed. I just have to take every opportunity I'm given. But here, you look around and think: 'what have I done'?"
Inter needed to at least match Borussia Dortmund’s result against Slavia Prague, but the Germans won 2-1 to move into the runner-up spot and consign Inter to a Europa League place.
"Watching that Ansu Fati goal is painful, as it killed us in every way. We were pushing, creating the chances to score and go 2-1 up," Inter boss Antonio Conte said.
"I was also disappointed for the fans at San Siro, as they pushed us from start to finish and created a wonderful atmosphere. It should've ended differently.
"I think we deserved more in this group. Still I think it's all valuable experience. We have to raise our heads again.
"We had the chances to win the game, we created those opportunities, but lacked that clinical edge to convert them.
“I have no complaints to make, as my players gave their all. We just lacked a goal and instead conceded at the other end to go 2-1 down, which really killed us."
Valverde rested Lionel Messi and several other key players for the trip to Milan, having already secured top spot in Group F.
Perez put the Spaniards in front on his Champions League debut after just 23 minutes before Lukaku levelled on the stroke of halftime.
Inter striker Lautaro Martinez had the ball in the net twice after the break, only for both goals to be disallowed for offside, before Fati smashed in a sublime finish inside the final five minutes.
Barcelona topped the group with 14 points ahead of Dortmund on 10, while Inter finish third on seven ahead of rock-bottom Slavia Prague on two.
Valverde left Messi, Sergi Roberto and Gerard Pique at home and the likes of Marc-Andre Ter Stegen, Luis Suarez, Sergio Busquets and Frenkie de Jong on the bench as he fielded a youthful side in an experimental 3-5-2 formation that mirrored Inter’s tactical set-up.
"There were many new things, between the players and the system. I made my choices based on the players I had available," Valverde said
"At the start Inter put us under great pressure, but little by little that intensity reduced and we managed to get into their half.".