First of all, I'm a hack at this so don't take my picks too seriously.
With that being said, I think Pella can win here. Cuevas had a long emotional win over Nadal that I believe will lead to a let-down in this match. Pella only needed 17 games to dispatch a streaking Thiem, who won in Buenos Aires (including a victory over Nadal) and hadn't gone to 3 sets in this tournament.