#1 Barcelona vs Manchester United

This is a dream match-up for the football lovers worldwide, but United would be wary of their own modest record against Barcelona. The Catalan giants beat United in the 2009 and 2011 Champions League finals, and would again start favorites this time around.
Lionel Messi and Luis Suarez have scored 36 and 20 goals respectively this season and might prove to a handful for United's defence. Moreover, Barca also have quality players like Gerard Pique, Jordi Alba, Ivan Rakitic and Sergio Busquets in their squad, and are always a very difficult team to beat. They beat Olympique Lyonnais 5-1 at Camp Nou in their round of 16 clash and remain almost invincible at home.
However, United have won 14 of their 19 matches under Ole Gunnar Solskjaer, and setbacks like the recent 0-2 defeat against Arsenal and the 2-1 defeat to Wolves should not affect their morale.
Moreover, United are likely to be bolstered by the return of injured players like Anthony Martial, Ander Herrera, Juan Mata and Jesse Lingard. They also played brilliantly to beat PSG 3-1 in Paris in the second leg of their Round of 16 tie. Paul Pogba and Marcus Rashford should be the two key players for them against Barca.
Their defence is also quite solid with players like Victor Lindelof, Ashley Young, Luke Shaw and Chris Smalling, and should be able to hold their own against the much-vaunted Barca attack. However, Messi’s presence alone is sufficient to make Barca the favorites to qualify for the semifinal at United’s expense.
Both Barca and United are traditional heavyweights of European football, and either of them can actually end up winning this year's Champions League. Barca are probably the most consistent team in European football now despite United being reinvigorated by the appointment of Solskjaer. The undeniable pedigree of the two clubs and the presence of some quality players in their respective squads make their clash a potentially mouth-watering one, and also the best this year's quarter-final stage has to offer.