#1 His performance in the final itself was also a differential
Having gone ahead early in the final against Tottenham, Liverpool were in cruise control for most of the match, keeping their opponents at bay without getting into second gear.
Spurs failed to register a shot at Liverpool's goal for most of the match as the Reds dominated proceedings, but all that changed with the introduction of Lucas Moura in the 66th minute.
Spurs finally tested Alisson in the 78th minute with a pile-driver by Son Heung-min from outside the box, and the former Roma shotstopper did well to parry the ball away from his goal.
Between then and the final whistle, Tottenham took control of the match, putting Liverpool on the backfoot until Divock Origi struck the all decisive second goal in the 87th minute.
In this brief ten-minute period of ascendancy, Tottenham managed to fire eight shots on target, but Alisson stood tall and proud, thwarting each of their attempts to equal the record of eight saves Manchester United's Edwin Van der Sar made in 2011 against Barcelona which is the most any keeper has managed in a Champions League final.
Liverpool's Champions League campaign in 2018 ended in tears, following two goalkeeping howlers by Karius. But fast forward a year later, and it ended in joy, courtesy of a superb eight-save performance by their goalkeeper. And this serves as further proof that Alisson was arguably the singular most important contributor to Liverpool's Champions League success.