There is less than a minute of stoppage time remaining at the Emirates Stadium and Arsenal have a corner. This is surely their last chance to find a winning goal against Sheffield United. But there is a problem. Gabriel Martinelli is down in some discomfort and doesn’t look like getting up.

The frustration in the stands is palpable. A delay is the last thing Arsenal need right now. But the groans give way to cheers when an irate David Luiz sprints over to his young countryman and hauls him to his feet, reminding him of the urgency of the situation and ordering him to carry on.

In the end, the corner did not provide the winner Arsenal needed. But the events which preceded it highlighted Luiz’s growing status in the team. When it was all over, he could be seen walking off the pitch with his arm around Martinelli’s shoulder. No hard feelings. Just a valuable lesson learnt.

Luiz drags Gabriel Martinelli to his feet against Sheffield United Luiz drags Gabriel Martinelli to his feet against Sheffield United Luiz drags Gabriel Martinelli to his feet against Sheffield United

Luiz was not wearing the captain’s armband on Saturday. That was given to Alexandre Lacazette in Pierre-Emerick Aubameyang’s absence. But the 32-year-old is fast becoming Arsenal’s true leader under Mikel Arteta.

“That’s what I wanted to demand of him,” said the Spaniard earlier this month. “He is a player that has won more trophies than anybody else in the dressing room and we have to use that in a very powerful way. I wanted him to step up. I wanted him to put all his qualities, his personality and experience towards the team and he has made a big step forward.”

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Sheffield United’s equaliser on Saturday was another reminder of Arsenal’s ongoing defensive issues. Arteta was without two senior full-backs for the game, while Sokratis had joined Calum Chambers on the sidelines and Rob Holding and Hector Bellerin were not deemed ready to start.