Arsenal boss Mikel Arteta said he was surprised the Gunners' Premier League opener with Brentford went ahead after a number of coronavirus cases at the club.

Pierre-Emerick Aubameyang, Alexandre Lacazette and Alex Runarsson all missed Friday's 2-0 loss after positive tests.

Willian is also recovering after returning a positive Covid-19 result.

Arteta said: "I was surprised but the regulations or the regulators decided the best thing to do was play."

Manchester City and Aston Villa had games moved because of Covid outbreaks last season.

Earlier this week, the Premier League said there had been 11 positive cases across two rounds of testing between 9 August and 15 August.

There is no out and out threshold for the number of positive cases which would cause a game to be called off but a club would need to contact the League to make such a request.

It is understood that Arsenal did not request a postponement. All players and staff were re-tested and there were no more positive cases so the game went ahead.

When Arteta was asked whether he or the club had requested for the game to be called off, he replied: "What we did is what we had to do, through the club, through the club doctor as well. He explained the situation, how it developed and the risk that we consider."

Arteta handed debuts to summer signings Ben White and Albert Sambi Lokonga against the Bees, while forward Folarin Balogun made his first Premier League start for Arsenal.

However, the Gunners put in a disappointing performance as Brentford celebrated their return to the top tier after a 74-year absence with a memorable win.

"We had an incredible 48 hours before the match which created a big uncertainty," Arteta added.

"It was probably an unprecedented Arsenal line-up."

Looking ahead to Arsenal's next game, Arteta said the players with Covid "had some tough days."

Aubameyang was back in training after recovering from coronavirus but Lacazette was yet to return as the squad prepare for Sunday's Premier League game against Chelsea.

Arteta added that most of his players have had both Covid-19 vaccinations and that the club was working on trying to get all playing staff vaccinated.

"Most of them are double vaccinated or had one vaccine," he said.

"We are trying to encourage them to get vaccinated and protect themselves and their families. It's a really personal matter, we are trying to guide them and explain the reasons why it is better to do but at the end it's a personal decision."