Arsenal journalist for PA Sport Mark Mann-Byrans spotted Mikel Arteta 'not too pleased' at Gabriel Martinelli after losing the ball cheaply against Brentford.

The Lowdown: Frustrating afternoon

It proved to be a frustrating afternoon for Martinelli at the Emirates Stadium, after he was substituted off for Leandro Trossard just after the hour mark.

He was taken off at a similar time in last weekend's 1-0 loss away at Everton in the Premier League, and may have been disheartened by the fact that his replacement scored the opening goal against Brentford.

The Latest: Arteta reaction

Taking to Twitter shortly before Martinelli was substituted, Mann-Byrans spotted Arteta's reaction to him losing the ball in his own half, saying he looked 'not too pleased':

"Martinelli losing the ball trying a neat flick in his own half. Safe to say Arteta was not too pleased."

The Verdict: Back to basics

Martinelli simply needs to get back to basics if he is going to rekindle his form from earlier in the season.

The Brazil international managed seven goals and two assists in the Premier League before this afternoon's 1-1 draw, but it is safe to say that he has not looked his best in the last couple of games, after being substituted around the hour mark by Arteta.

With Trossard scoring, the manager now has a big decision to make over whether to keep the faith with Martinelli by starting him in a crucial match against Manchester City in midweek, or take him out of the firing line and start the more in-form player in the Belgian.