(CNN)When your team is about to face Barcelona there is a question that is always asked of the opposing manager: “How do you stop Lionel Messi?” For 74 minutes of the first leg of its Champions League semifinal on Wednesday, Liverpool appeared to have found an answer. Follow @cnnsport For much of the night, Messi was on the periphery of the contest, struggling to find a way to make an impact on a highly charged contest at the Camp Nou. And yet, in seven second-half minutes, it all changed. Two goals from the magician, his 599th and 600th for the club, ensured Barcelona claimed a 3-0 victory and all but ended Liverpool’s hopes of making a second successive final. Messi scores his second goal in the 3-0 win over Liverpool. Messi’s first may have been fortuitous, but his second, an exquisite free kick that defied belief, was pure box office. Read More The scoreline was cruel on Liverpool, which had chances to score throughout the contest, but was ultimately made to pay the price for its profligacy in front of goal. Even at 3-0 down, Liverpool had chances with Roberto Firmino’s effort hacked off the line and Mohamed Salah striking…