Emi Martinez believes Eddie Nketiah's late sending-off against Leicester was "harsh", insisting the 21-year-old "slipped" as the Gunners threw away a lead in a 1-1 draw against Leicester.
The 21-year-old was brought on alongside Joe Willock in the 71st minute with Mikel Arteta's side 1-0 up and edging towards sixth place and a fifth consecutive win.
Mikel Arteta was forced into a quick rethink, however, with the forward shown a red card just four minutes later, referee Chris Kavanagh - with the help of the pitch-side monitor - deeming the challenge on James Justin to be serious foul play following a VAR review.
Vardy made the home side pay five minutes from time in what was his 22nd goal of the season, also his 10th against Arsenal in as many starts.
Martinez - who missed out on a seventh clean sheet in his ninth Premier League start for Arsenal - insisted his side were "outstanding", however, and deserved to win the game.
"100 per cent [we should have won]," he told BBC Sport. "Before Eddie Nketiah got sent off we played an outstanding game and should have scored two or there goals.
"We defended well and have to be happy with a draw, we wanted to win.
"I know Eddie, he is not an aggressive player. He slipped and did not want to injure him and the red card is harsh. We know Eddie and we know he is a nice guy.
"Sometimes you score, sometimes you don't. Before the red card we looked solid and I did not have to make a save in the second half.
"I know I am going to concede goals but hopefully I can keep more clean sheets for this club. That is one thing we have to work on and disappointed to concede at the end."
