The winger said the team has been following his brother and team-mate Inaki Williams’ advice during their Europa League run this season.
“From the start we have been keeping a low profile — my brother said it last year, ‘keep it low-key’,” said Nico Williams.
“I understand the excitement of the fans but we need to be 100 percent focused on the game and on our job.
“We will give our souls to reach that final at San Mames.”
Athletic host Ruben Amorim’s United at San Mames on Thursday in the semi-final first leg, before the return at Old Trafford next week.
Nico Williams said it was hard not to get excited about the clash with the Premier League heavyweights, despite the Red Devils’ poor domestic form this season.
“United is a great team with great players, such as Bruno Fernandes,” continued Nico Williams.
“There is a lot of excitement in the dressing room, as well as throughout the city and among the entire Athletic family.”
Athletic have never won a European trophy but have twice lost a Europa League final, including in 2012 when they beat United along the way.
Last year they won the Copa del Rey, ending a 40-year wait for a major trophy, while Williams claimed the Euro 2024 title with Spain, scoring in the final against England.
“It’s in the big games that the great players appear,” added Nico Williams.
“I’m looking forward to tomorrow and also to the game at Old Trafford.”
Athletic coach Ernesto Valverde warned his players that no matter what they accomplish on Thursday, it will only be half-time in the tie.
“Whatever happens, the tie will be decided in the second leg,” he said.
“You have to play two good matches to advance, and tomorrow is the first of them.
“It is an important match for the season and also in the club’s history.”
United produced an astonishing comeback to beat Lyon in extra time at Old Trafford in the quarter-finals, with three goals in eight minutes, just when it looked like they were heading out.
“In these competitions, a mistake or one bad minute can send you out,” added Valverde.
“These are knock-out phases, and you need to know how to play and manage them.”
Valverde recalled United’s famous 1999 Champions League final triumph against Bayern Munich, with the English side netting two stoppage-time goals to snatch victory.
“We know they’re capable of winning a European Cup in a minute,” added Valverde.
“We will take that into account… I don’t know who the favourite (to progress) is.”
By AFP
