Leo Messi had a brace here Tuesday to lead Barcelona 3-0 over Manchester United for a 4-0 aggregate victory in their Champions League quarterfinal tie.
The largest crowd of the season - 96,708 - filled the stands at Camp Nou with the expectation of seeing Barça advance to the final four of Europe's elite club tournament for the first time since 2015.
The Argentine superstar proved himself equal to the occasion.
Messi, who hadn't scored in a Champions League quarterfinal match since 2013, posted a pair of goals in less than five minutes to settle the contest.
Already through to the Copa del Rey final and leading LaLiga by 9 points with six matches left in the season, Barcelona and their supporters are dreaming of the treble.
Seven clubs have achieved the continental treble - Europe, domestic league and main domestic cup competition - since 1967, but only Barça have done it twice.
But the night did not begin well for the hosts, as United set the pace for the first 15 minutes. Only the cross-bar kept Marcus Rashford from leveling the tie at 1-1 just 36 seconds after the opening whistle.
Looking like a different team from the one that lost 1-0 last week at Old Trafford, the visitors were relentless on the attack.
Barcelona appeared to catch a break in the 11th minute when the referee awarded a penalty after United's Fred fouled Ivan Rakitic, but the VAR evidence persuaded him to reverse course and Rashford forced a stop from Barça goalkeeper Marc-Andre ter Stegen on the ensuing sequence.
United's Phil Jones headed away a strike by Luis Suarez in the 15th minute.
Seconds later, however, Messi snagged the ball in midfield, nutmegged Fred, feinted to draw Jones out of position and directed a low shot to the far post to put Barça up 2-0 on aggregate.
The advantage grew to 3-0 in the 20th minute, as the ball fell to Messi and he evaded Jones before slipping a shot under United keeper David De Gea, who spectacularly misjudged the situation and made the wrong move.
Barcelona made the running for the rest of the first half and would have scored again right before the break if De Gea hadn't got his head in the way of Sergio Roberto's shot.
Ashley Young denied Messi's bid for a hat trick three minutes after the re-start.
Manchester United won a corner in the 54th minute, but the chance came to nothing and Philippe Coutinho put the final nail in the coffin in the 61st minute, with an assist from Messi.
FC Barcelona: Ter Stegen; Sergi Roberto (Semedo, m.71), Pique, Lenglet, Alba; Busquets, Rakitic, Arthur (Arturo Vidal, m.75); Messi, Suarez and Coutinho (Dembele, m.81).
Manchester United: De Gea; Jones, Lindelof, Smalling, Young; Fred, McTominay, Pogba; Lingard (Alexis Sanchez, m.80), Rashford (Lukaku, m.73) and Martial (Dalot, m.65).