Alexis Mac Allister admitted he was “a little nervous” before his penalty which sparked delirium at the Amex.

But he held his nerve to thump home a winner against Manchester United that Albion fans will treasure for years.

The Argentina international crashed his spot kick past the outstanding David De Gea deep into added time to secure a tense 1-0 success.

The win completed Albion’s first ever DOUBLE over United.

And it came less than a fortnight after United edged out the Seagulls in the FA Cup semi-final at Wembley.

Mac Allister told Sky Sports: “It was similar to Wembley, we did everything to win the game but we couldn’t score our chances but at the end we got the penalty so it was a nice win.

“Of course I was a little bit nervous. Last minute, everyone was going to talk about this.”

Mac Allister was outstanding even before his spot kick conversion and was denied very late on by a brilliant De Gea save.

He said: “It’s easier to play in this team, the way we play is very nice.

“My team-mates are fantastic so it’s down to them as well.

“I am very pleased to play alongside them and they help me to be a better player.”

Mac Allister, who has been speculatively linked with a summer move, spoke of what playing for Albion means to him.

He said: "I’ve been here three-and-a-half years already and I know what this club gave to me.

“I am very grateful, very happy to be here and I try to transmit that to my team-mates, to the young players, the South American players.

“It´s a fantastic team, it’s like a family so every time I get to the pitch I really enjoy playing here.”

(Additional reporting: Carlos Acosta Juckes)