Jurgen Klopp's side warmed up for next Saturday's Premier League opener at Watford with an emphatic friendly victory.
Jurgen Klopp's side warmed up for next Saturday's Premier League opener at Watford with an emphatic friendly victory, leaving them unbeaten inside 90 minutes over eight games that included a 3-0 win over German champions Bayern Munich.
The Reds went into an early lead through Roberto Firmino, before Inaki Williams levelled before half time.
Klopp made 10 changes at the break, and teenage duo Ben Woodburn and Dominic Solanke added two more goals to seal victory.
The Premier League side were up against a weakened opposition, with the Spaniards making 11 changes to the side that beat Dinamo Bucharest in the Europa League on Thursday.
Liverpool were without the injured Daniel Sturridge, Philippe Coutinho, a possible transfer target for Barcelona, and Adam Lallana, but still fielded a strong team.
Belgium striker Divock Origi should have had the Reds ahead inside 10 minutes when Joel Matip delivered a perfectly weighted slide pass to put him through on goal.
But the striker pulled his attempt wide, and after Alberto Moreno and Mohamed Salah combined to set him up again five minutes later, the 22-year-old headed wide again.
The opening goal didn't take long to come, with Firmino, who scored twice from the spot in midweek against Atletico Madrid, doing so once more after Inigo Lekue conceded a soft penalty by grappling with the Brazilian.
Bilbao were threatening on the counter attack against a rocky Liverpool defence, with Inaki Williams setting up Ager Aketxe, but stretching to connect his shot went wide of Simon Mignolet's goal.
Williams reacted with frustration but made up for it moments later when he blocked Dejan Lovren's attempted clearance and placed a controlled finish past Mignolet to level the score.
Firmino put Moreno through on Kepa Arrizabalaga just before the break but the full back, who had been impressive in attack, fired right at the goalkeeper.
Bilbao forward Cordoba who had the first shot on target after the break, unfortunately for him it was right at Mignolet.
Sadio Mane's close range strike was then pushed over by Arrizabalaga, but the keeper could do nothing about Woodburn's goal just before the hour.
Solanke raced behind his opposition full back and pulled back for the 17 year old, who took one touch before rifling past Arrizabalaga to regain the lead for the Reds.
Ragnar Klavan returned the favour to Solanke with 10 minutes to go, chipping an inch perfect cross for the England U20 man to head home.