Arsenal manager Mikel Arteta says there are "no number ones" in his squad after signing goalkeeper David Raya.

The 27-year-old has signed from Brentford on a season-long loan which could be made permanent.

Arteta is hoping to increase competition in his goal with Raya challenging England keeper Aaron Ramsdale.

"To be better [as a team], the environment has to be better," Arteta said.

Ramsdale, 25, kept 14 clean sheets last season as Arsenal finished runners-up to Manchester City, but Arteta said he hoped Raya's arrival and greater competition for places in his squad will lift his players to improve their level of performance.

"When you have to be at 100% every day, believe me, your level increases," the former Everton and Real Sociedad midfielder said.

"We have two great goalkeepers, just like we have two great left wingers, two great holding midfielders, two great strikers. There is no number one - not in any position."

Defender Jurrien Timber requires surgery on his injured ACL he sustained in the opening day win over Nottingham Forest on Saturday.

"What happened to Jurrien can happen to anyone. If Aaron [Ramsdale] did his cruciate, we have to be prepared and proactive. Now, we have two excellent goalkeepers who exactly fit our model."

Former Manchester United goalkeeper Peter Schmeichel doubts the benefit of competition between the sticks, and told BBC Radio 5 Live: "Ramsdale was fantastic for Arsenal last season; he's brilliant with his feet and he's brilliant with the core business of goalkeeping. He is the best English keeper."

"The goalkeeper's position is very reactive. You cannot create anything on your own; you have to wait for things to happen. You're now asking your goalkeeper to prove he's better than the other one, that means you now have to go out and do stuff - and you don't want that.

"It's the one position that you want to be steady. The worst thing is when a goalkeeper tries to do something and it goes wrong. Every time, it's a goal.

"I don't understand why Arteta would create this potential problem."