Arsenal manager Mikel Arteta labelled the decision to award Sunderland a penalty "unacceptable" on Saturday after watching his side grind out a 2-0 win to maintain their 100% start to the season and move clear at the top of the Premier League.
As it was, keeper David Raya pushed Enzo Le Fee's spot kick against the post in the 55th minute and two minutes later Bruno Guimaraes scored his first goal for the club.
Bukayo Saka wrapped it up deep in stoppage time from the penalty spot to make it four leagues wins out of four for the reigning champions.
It could have been different had Le Fee found the net, but Arteta blasted the decision by referee John Brooks to award a penalty when Ezri Konsa was penalized for pulling down Dan Ballard as a corner was played in.
"It was a huge win, but it could have been something very different," an angry Arteta told TNT Sport when referring to the penalty award.
"It's unacceptable at this level, this can change the course of a season and the championship. It's not acceptable. I've seen it 10 times to make sure and it's not possible at this level that it can be a penalty. It cannot happen.
"It's not a penalty in any context, in any league."
It was far from a vintage Arsenal display against a tenacious Sunderland, who deserved something for their endeavor, but they dug deep and showed the resilience that helped them win a first title for 22 years last season.
They have now kept four clean sheets in their five games since the start of the season, including in the Champions League win at Napoli in midweek.
Summer signing Guimaraes replaced Myles Lewis-Skelly at halftime and made a stunning impact.
After receiving a pass from Declan Rice, he sent a right-footed curler into the top corner.
Arsenal were forced to defend desperately at times as Sunderland's physicality rattled them, but Saka netted his third goal of the season when he beat Robin Roefs with his spot kick after being fouled by Reinildo Mandava who was sent off.
"It's unbelievable the spirit and the courage we have to go again and again and again," Arteta said. "So pleased in one sense and so worried in another.
"David Raya was unbelievable. He is a player that decides football matches when we need it.
"Sunderland deserve a lot of credit for the way they make it so hard for you."
Manchester City, the only other side not to have dropped Premier League points this season, can join Arsenal on 12 points if they beat Manchester United on Sunday.
