Anthony Martial is something of a footballing enigma.
When he first arrived at Manchester United from Monaco for an initial £36million (BBC), plenty of eyebrows were raised. However they were replaced by shrieks of delight when the Frenchman scored against Liverpool on his Old Trafford debut.
Martial was brilliant in his first season under Louis van Gaal, finishing with 17 goals. It was supposed to be the start of something magical, but the striker has failed to replicate that form since.
Eight goals in 42 outings the following season was followed by 11 in 45 appearances last time round. In short, it was good but not great, and far from what United fans expected after that glorious debut campaign.
The issue for Martial, at least under Jose Mourinho, is that he is no longer a regular starter. The arrival of Alexis Sanchez and presence of Romelu Lukaku has seen to that. And his early touches against Young Boys hinted at a player bereft of confidence.
For the first 20 minutes on Wednesday the 22-year-old was out of sorts. But the longer the game went on, the more we saw the Martial of old, and by the final whistle he had both a goal and a swagger.
Mourinho knows what Martial needs to be a United great, because it was clear for all to see this week.
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He needs to start regularly, to build his confidence and rediscover what he had in abundance under van Gaal.
Martial is not an impact player. He cannot sit for 70 minutes with his feet up week in, week out, and excel for a few minutes here and there.
The United star is a confidence player and that was evident against Young Boys. To start with he tried things and failed. Yet he kept trying. And in the second half he was running rings around his opponents.
With only two Premier League appearances (amounting to 79 minutes) this season, Martial looks a shadow of his former self. But, if he gets more starts, the player we saw on Wednesday could be the norm rather than the exception.