Ruben Amorim has been true to his word in giving chances to all of his Manchester United players, but the longer he spends in the Old Trafford hotseat the closer he must be to understanding his strongest team.

Some selection decisions have certainly become a little clearer after a crucial 2-1 win against Viktoria Plzen in the Europa League that owed a lot to the head coach's own ability to change a game. Some of his starting XI in the Czech Republic didn't exactly enhance their claims for more regular action.

Rasmus Hojlund was the two-goal hero, coming off the bench to turn the game around, and his 34-minute cameo provided a stark contrast with Joshua Zirkzee, who played 56 minutes as centre-forward, then five more behind Hojlund before his evening came to an early end.

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Zirkzee gave the ball away 16 times in the first half and some of his general play was just so tardy. There were flashes of quality, the odd moment of smart hold-up play, but it was nowhere near enough.

The £35m striker gives the impression of someone strolling through games. He plays like he's playing an age-group game against youngsters shorter and slower than he is. It can give the illusion of being just a little too casual and that simply doesn't fit into Amorim's high-octane style.

Zirkzee's double against Everton was encouraging, but it might just prove to be a red herring. He doesn't press with enough intensity and doesn't offer enough energy. It's difficult to see how he has a future in this side under Amorim, even if he does offer flexibility as a striker or as one of the No. 10s.

The contrast with United's attack when Hojlund came on was certainly illuminating. Yes, they were chasing the game, but there was a clear shift in intensity. The Dane offered a more central, more physical threat than Zirkzee. His first goal was a tap-in but he occupied central defenders and caused problems.

He also gave them a threat in behind and helped shift the team up the pitch. Too often in the first half, United had Zirkzee, Marcus Rashford and Amad coming towards the ball. It made it all too easy for Plzen to defend against.

With Hojlund on, they had to drop deeper to guard against his runs in behind. In turn, that allowed Amad more space to dribble into. That was the combination that led to the equaliser and threatened to provide a winner.

As space opened up, Amad thrived. Another excellent run teed up Mason Mount for a big chance, only for Martin Jedlicka in the Plzen goal to thwart him.

Amorim has made a habit of rotating his cast at United, doing so for a couple of reasons. He wants to give every player the chance to impress and show what they can do in his system, but he has also said these players can't carry out his physical demands, which is why they are being chopped and changed.

There have been 26 alterations in the five games since his first in charge against Ipswich and more will be coming at the Etihad this weekend. The presence of Manuel Ugarte, Kobbie Mainoo and Hojlund on the bench suggested they were likely starters.

After this performance, Hojlund's name should now be inked in as the most dangerous striker at the club, with Amad next to him, enjoying the space the Dane can create. They could be key to exploiting any defensive weaknesses against a City side who have won just one of their last 10 games.