Trossard led the line away to Girona in the Champions League when Havertz was rested last month and played centrally just off the German during a run of games last autumn, when Arsenal shifted to a 4-2-2-2 system to accommodate Martin Odegaard’s absence from midfield.

Arsenal took a clear and collective decision not to invest last month. That decision now appears set to haunt them

Arsenal’s Premier League title challenge has been dealt a blow after forward Kai Havertz was ruled out for the season with a hamstring injury.