#3 Jurgen Klopp gets his tactics wrong
It is on rare occasions that a tactical genius such as Jurgen Klopp gets his tactics wrong and unfortunately for Liverpool, this was one of those nights, and it might have cost them a spot in the Champions League finals.
Klopp set his side up in their usual 4-3-3 formation but with Gini Wijnaldum taking the place of Roberto Firminho in the False-9 role to enable Liverpool to press higher in a rapid manner to force Barcelona's defense to make silly mistakes which can be capitalized by the deadly duo of Mane and Salah.
The plan backfired as Wijnaldum proved to be ineffective and was comfortably managed by Barcelona's center-backs Gerard Pique and Clement Lenglet till he was substituted during the 79th minute.
Roberto Firminho not only offers a more potent outlet to finish moves than Wijnaldum but also provides good link-up play with both Mane and Salah along with making timely runs to offer more space for the duo to work with, something Liverpool desperately missed.
Another error which might have cost them is Klopp's preference to start Joe Gomez, who has recently recovered from a lower leg fracture, over Trent Alexander Arnold as Jordi Alba and Coutinho found more space down the right due to his lack of pace.
Alexander Arnold has put in good shifts during the period that Gomez was injured and could have handled the pace and guile of Alba and Coutinho hence putting less pressure on Matip and Van Dijk.