Lukaku at the double as Man United overcome VAR controversy

Having lost 2-1 at Huddersfield in the Premier League last October, United approached this game with more determination and conviction and took the lead inside three minutes when Lukaku showed strength and poise after latching on to Juan Mata's through ball.

Mata looked to have doubled the advantage on 45 minutes before his goal was ruled out for offside by VAR, albeit with little conclusive evidence.

But with Huddersfield struggling to mount a sustained assault on Sergio Romero in the United goal, Lukaku made the tie safe for the visitors by rounding off a 55th-minute counter-attacking move, which also involved Alexis Sanchez, by sprinting more than half the length of the pitch to score.

United were boosted by the return of Eric Bailly, who missed three months with an ankle injury, as a stoppage-time substitute. Mourinho will hope to have Pogba, Ander Herrera and Marcus Rashford fit for Wednesday's Champions League round-of-16 first leg against Sevilla.

2. More VAR controversy

It is important to stress that the video assistant referee (VAR) system is currently in a trial period in English football, so teething problems should be expected. Yet when it has been deployed in recent weeks, it has only seemed to bring more confusion to matters, rather than clarity.

In this game, Juan Mata's "goal" for United on the stroke of half-time was eventually disallowed by referee Kevin Friend for offside, but it was a tight decision and one that even freeze-framed television reviews failed to confirm convincingly.

VAR is only supposed to be called upon whenever the officials have made an obvious error, but neither Friend nor his assistant can be accused of that. Moreover, while Friend was talked through the incident by Neil Swarbrick, the John Smith's Stadium waited -- and waited -- for resolution, due to the lack of replays inside the ground.

Friend eventually chalked off the goal, but replays continued to be inconclusive. Was Mata's knee just ahead of the last defender when Ashley Young passed? Perhaps, but this was far from an obvious error. Meanwhile, what were those squiggly lines running across the pitch on TV screens?

It was all too bewildering and even more so when you consider that VAR did not overrule an incident earlier in the first half when Chris Smalling handled Philip Billing's long throw. As such, while United missed out on a goal because of replay, the home side were denied a penalty.

Just a reminder: VAR is supposed to end confusion and bring clarity.

3. Nervous night for Smalling, Lindelof

This was a big game for the two men at the heart of United's back four. Smalling went into the cup tie after a horror show at Newcastle, when his dismal performance included conceding the free kick, from which the home side scored, with a dive; it all highlighted why England manager Gareth Southgate publicly raised his doubts over the defender's ability earlier this season.

As for Victor Lindelof, the Sweden international has struggled to convince United supporters of his quality since an error-ridden display at Huddersfield in that league defeat last October. As such, pairing Smalling and Lindelof together was a gamble by Mourinho, considering neither player could possibly enjoying peak confidence.

And both had moments where their lack of form came to the fore: Smalling's shortcomings were mainly misjudged headers, the aforementioned handball that should have led to a Huddersfield penalty and a general look of edginess when in possession.

Lindelof, however, looked even more nervous, and there was one moment in the first half when Smalling did a 270-degree turn to pass to goalkeeper Sergio Romero rather than his unmarked defensive partner, who was shouting for the ball 20 yards away.

In the biggest games, Mourinho is likely to favour Bailly, Marcos Rojo or Phil Jones. But, if injuries bite, Smalling and Lindelof might have to be trusted against top-class opponents, and that will be a worry for the United manager.