Tottenham ace left a big impression.
Ajax star Frenkie de Jong has been reflecting on what went wrong in the semi-final.
He put it down to a combination of bad luck, and Lucas' brilliance.
De Jong told Voetball Primeur: "We were no longer playing football. Everything went long. Then it becomes difficult.
"Spurs also has a lot of physical strength. In the end the game just went wrong. Three times Moura ... He is a very good player, very explosive."
It was Lucas' second hat-trick for Spurs, following up three goals he scored at home to Huddersfield a few weeks earlier.
This one came with far more at stake in a bigger game, and that made it so much more impressive.
Ajax bounced back at the weekend to beat Utrecht in the Eredivisie, and are now closing in on the title.
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