Brighton's Matt O'Riley to undergo surgery on injured ankle

O'Riley, who signed from Celtic earlier this week, was substituted during the Seagulls' Carabao Cup victory over Crawley on Tuesday.

"It's like we expected, a bad injury," Hurzeler said in a press conference on Thursday morning.

"He needs surgery on his ankle. I can't say how long we expect him to be out. We have to look how the rehab will go.

"But of course it's a tough one for us, we will try to support him the best way we can. We tried to get him as fast as possible on the pitch, and let's hope he will be back soon. It's terrible luck for Matt and the club."

Former Fulham academy graduate O'Riley had a hand in 31 goals in the Scottish top-flight for Celtic last season.

He netted during Celtic's pre-season friendly victory against Chelsea and Hurzeler credited the Denmark midfielder's attitude after his injury in Brighton's 4-0 victory in midweek.

"I had a small chat with him yesterday, it's not the best situation," he added.

"He's very, very disappointed, but he is a good character, and he's a very positive guy, and immediately he's looking to the future and says that he will be back soon and he'll come back stronger.

"That's a very positive thing. I like his attitude. It is very important that you also stay mentally strong in tough moments like this because you can't change it in the end, that's why I think he will come back strong."

Brighton face Arsenal on Saturday, with both sides having won their first two Premier League matches of the season.

Hurzeler believes Mikel Arteta's men are among the best teams in the world.

He said: "They're one of the best teams in the world at the moment,

"They don't have a lot of weaknesses, they have quality and solutions for all phases."