Liverpool's tortuous journey to Spain ended with a narrow 1-0 defeat to Atletico Madrid in their Europa League semi-final first leg tie. Former Manchester United striker enjoyed an early moment of good fortune when his initial mishit shot fell kindly for him to scuff the ball into goal past a despairing Jamie Carragher on the line.
Forlan almost doubled his tally but Pepe Reina easily saved.
Liverpool themselves rarely threatened and were grateful to Reina for a fine stop to keep out Simao Sabrosa's half-volley.
The Reds did see Yossi Benayoun have a 'legitimate' goal disallowed after being flagged offside midway through the first-half but generally Liverpool failed to inspire and must look for an improved performance at Anfield next week.
Rafa Benitez told "I'm disappointed we conceded a goal and didn't manage one ourselves.
"They had chances, we had chances. Half time.
"Yes the goal was a strange one but we have the second leg at Anfield and it will be totally different.
As to the disallowed Benayoun goal.
"I think he was onside, people were telling me he was onside, but that was one of a few things we were not happy with. But in football you cannot change things after the game.
"I'm confident for the next game at Anfield, with the fans behind us we can beat anyone."