Arsene Wenger believes a "scandalous" penalty was the main reason why his Arsenal side ended up losing 2-1 at Watford on Saturday.

The result lifted Marco Silva's Hornets into fourth place in the Premier League  on a day when Manchester United, Liverpool and Chelsea also all dropped points.

Arsenal led at half-time through a rare goal from Per Mertesacker, the Germany defender, but the game changed in the second half when Mesut Ozil failed to convert a simple chance to double the lead.

Within a minute Hector Bellerin was adjudged to have impeded Richarlison at the other end for a penalty that the Arsenal manager was convinced was the result of a dive to deceive referee Neil Swarbrick.

Measures are in place this season for the authorities to punish simulation retrospectively and it will be interesting to see if action is taken against the Brazilian.

"It's a scandalous decision but what can we do? Nothing," Wenger complained. "I believe that we had many many danger situations where we could have scored but didn't.

"We were unlucky with the penalty it was a bit ridiculous. Then we panicked. And we stand there with defeat.

"We dropped the level a bit in the second half. We lost our fluency a little. We had the chances to score two and three."

Richarlison could be handed a two-match ban if found guilty of diving, a decision that would be made by a three-man panel consisting of a former match official, a former manager and an ex-player, and would have to be unanimous.

- 'Diving and deceiving' -

Former Premier League referee Graham Poll certainly felt there was a case to answer. "It is as clear an example of diving as you can see," he said. "I wouldn't blame Swarbrick. I would blame Richarlison for diving and deceiving."

The penalty was converted by Troy Deeney, a Watford substitute, and set the platform for midfielder Tom Cleverley to win the game deep into added time.

Deeney was convinced Swarbrick had got the controversial penalty call correct. "I know Hector, he's a good lad but that's a penalty and the other way round he'd be screaming for a penalty," he said.

The season may only be eight league games old but there is no denying that Watford have made a fine start under new manager Silva, apart from a 6-0 home loss to Manchester City last month.

"It's not bad but it means nothing now," Deeney said. "We're just taking it game by game. I believe we're building something really good.

"With late goals it shows we have belief and how fit we are. All the lads coming in are making the impact."

Silva, who almost kept Hull City up last season on the back of strong home form, revealed he had been critical of his players at half-time.

"It was a very good second half," he said. "I didn't like the first. We were playing a very good team and we played scared and without confidence.

"We spoke at half-time and I told them not to be shy. The second half we played very well and with our attitude we could change the result."

"Massive credit has to go to the manager," Deeney added. "It's called a half-time team-talk but that was a roasting.

"He told people to believe. We had a great start to the season and wanted to carry on against the bigger teams."

Source: AFP