Arsenal suffered their first defeat of the season as they were stunned by Brighton in a 3-0 defeat, which allowed title rivals Manchester City to jump to the top of the table after a win over Sunderland.
Manager Mikel Arteta said that he was “extremely disappointed” with his side’s performance, which has put a serious dent in their title hopes as City aim to run away with it this season.
Summer signing Guimaraes started next to Declan Rice in the heart of midfield during the Brighton clash but was replaced after 60 minutes after a poor performance in which Arteta said his role on the pitch “didn't work”.
Speaking after the clash, the Brazilian midfielder revealed that Arsenal simply weren’t good enough and that champions should never playu the way they did.
Guimaraes described the game as a "bad day at the office" and offered a direct apology to fans after the final whistle.
"We are very disappointed, and we have to learn from our mistakes because we were far away off our level," he stated.
"We were too sloppy with the ball, didn't win any duels. And we cannot accept this while wearing this shirt of a champion. We cannot repeat this.
"It's a lesson for us because I think we've been on a good run so far," he added. "We'd won every game, but this is a game to forget and we have to improve."
The Gunners had conceded just one goal in the league this term during their impressive winning streak, but after suffering 3 against The Seagulls, Arteta’s side may be showing signs of cracks that must be smoothed over.