Arsene Wenger hit out at a "scandalous" penalty decision after Arsenal crashed to a last-gasp defeat at Watford.
The Gunners were leading through a first-half header from Per Mertesacker when Hector Bellerin tangled with Richarlison in the area.
Watford's Brazilian winger hit the deck and referee Neil Swarbrick pointed to the spot, with substitute Troy Deeney doing the honours.
The Hornets then secured all three points in stoppage time when Tom Cleverley pounced on a loose ball and fired home.
But it was the penalty decision which swung the game and left Wenger fuming.
"I would say it was not a penalty. It was a decision from the referee and that's it," said the Gunners boss.
"It is a scandalous decision. It came at a moment in the game where it was absolutely important for Watford. No penalty, no goal."
Watford manager Marco Silva was quick to defend his player, however.
"I have seen the penalty now and I respect the decision of the referee," he said.
"It's important, I didn't see a dive or a simulation.
"Richarlison has suffered the most fouls in the Premier League this season, and people are starting to say he dives.
"He is not. He is fair, He wins fouls like the best players in the world win fouls."
Mertesacker looked set to be the unlikely hero when he nodded in his first Premier League goal since December 2013.
The German defender, making his first league start in 532 days, powered home a header from a corner six minutes before half-time.
Mesut Ozil, on as a substitute, should have settled matters when he was sent clean through but he shot too close to Heurelho Gomes.
Moments later came the penalty drama, and then in injury time when Andre Carrillo's shot was blocked Cleverley lashed in a dramatic winner.
"I thought we played very well in the first half but I was not so happy with the level in the second half," added Wenger.
"I think our level dropped in the second half and we missed many chances to kill the game.
"After that, at 1-1, there was no need to panic. I believe that on the second goal we can only look at ourselves."
Arsenal were attempting to climb into the top four but instead it is the Hornets who find themselves in the Champions League spots.
Nevertheless, Silva said: "I don't change what I said at the start of the season.
"We have one goal, to remain as a Premier League club. It's too early to change."