BARCELONA: United were undone twice in four minutes by Messi, who first nicked the ball off the careless Ashley Young and then watched as a weak shot from distance squirmed underneath David de Gea.
Lionel Messi pounced on two Manchester United mistakes to score twice and end their hopes of another comeback at Camp Nou as Barcelona breezed into the Champions League semi-finals on Tuesday.
Philippe Coutinho, in perhaps his best performance of the season, added a third with a curling effort into the top corner and by the end, an outclassed United might have been relieved the score was not more traumatic than 3-0, 4-0 on aggregate.
Liverpool, who take a 2-0 lead to Porto on Wednesday, are now the most likely obstacle between them and their first Champions League final since they last won this tournament in 2015. Mohamed Salah and Sadio Mane might feel emboldened.
United were brilliant for eight minutes and could have been ahead within 30 seconds as Rashford raced onto a curving Paul Pogba pass and toed away a shot, which Marc-Andre ter Stegen bravely left to graze his own crossbar.
Then, Barcelona had their own eight-minute flurry as United almost conceded a penalty, ruled out after Fred took the ball before bringing down Ivan Rakitic, and then did concede, twice, to Messi.
Both could have been avoided, even if Young’s turn on the edge of his own box was punished in devastating fashion. Young lunged in to atone for his mistake but Messi skipped away from him, poked it through Fred’s legs and then whipped the ball into the corner.
The second was simpler. Fred and Scott McTominay closed in on Coutinho and the ball spilled out to Messi, whose dribbling shot with his right foot should have drawn a routine save. Instead, De Gea let it squirm under his body for 2-0.
Pogba lashed out at the increasingly influential Arthur and Barca could have had a third before half-time, De Gea scrambling across to save on the line when Sergi Roberto should have finished. Messi could have had his hat-trick too after Luis Suarez found him with a superb cutback and there was an almost comical sequence in the second half when the Argentinian played with his United chasers before finally being bundled over by McTominay.