One week on from thumping the Czech champions 5-1 in the first leg of their last-16 tie, the Reds bettered their previous tally with a 6-1 second-leg thumping at Anfield, soaring into the quarter-finals 11-2 on aggregate.
Four of Liverpool's goals arrived during the first 14 minutes of the match, where Clark opened his senior Reds account with a crisp low strike after Mohamed Salah intercepted a loose pass from Ladislav Krejci.
The 2005-born protege subsequently turned provider for a record-breaking Salah goal thanks to another defensive howler from Sparta, who also conceded to Darwin Nunez and Cody Gakpo in that 14-minute annihilation.
Veljko Birmancevic got the visitors on the board on the stroke of half time, but Gakpo's second and a deflected Dominik Szoboszlai strike in the second half capped off an emphatic Liverpool triumph, albeit one that was slightly marred by Clark's withdrawal.
Klopp had intended to bring Salah off for 20-year-old debutant Mateusz Musialowski for his final substitution, but Clark appeared to have hurt his ankle and was withdrawn instead, thus forcing Salah to complete an unplanned 90 minutes.
Speaking to TNT Sports, Klopp confirmed that the Egyptian had come through unscathed, and while he is concerned about Clark's issue, he is keeping his fingers crossed that the teenager has avoided something serious.
«He played incredibly. It was his first goal but he won the ball back after another one. He is the one I am worried a bit about, we wanted to take off Mo [Salah], but Bobby sits on the ground and says
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